Eng. Sci.

, 2020, 12, 52–78

Engineered Science
DOI: https://dx.doi.org/10.30919/es8d1126

Chemically Deposited CuInSe2 Thin Films and their Photovoltaic

Properties: A Review
Balasaheb M. Palve,1 Chaitali V. Jagtap,1 Vishal S. Kadam,1 Chandrakant D. Lokhande2 and Habib M. Pathan1,*

Abstract

Copper Indium di-Selenium, CuInSe2 (CISe), is the most promising absorber material for thin-film solar cells. CISe based solar
cells have shown long-term stability and the highest conversion efficiency of all thin-film solar cells, above 19%. Moreover,
CISe based solar cells are very stable and thus their operational lifetimes are long. The deposition method generally has a
large impact on the resulting film properties as well as on the production costs. CISe can be prepared by a variety of methods
like physical and chemical methods. The present review discusses first the liquid phase synthesis method like chemical bath
deposition (CBD), electro-deposition (ED), spray pyrolysis (SP), and successive ionic layer adsorption and reaction method
(SILAR), etc. Next, the structural, optical, electrical, and photo-electrochemical properties of CISe, as well as the features of
solar cells made thereof are reviewed. The last part of the text deals with the application of CISe thin-film absorbers in solar
cells. The photo-response properties of the CISe are discussed how they can improve the efficiency and reduce the cost in
potential applications.
Keywords: CISe; Solar cell; Thin film; Chemical method; Photo-electrochemical.
Received: 10 August 2020; Accepted: 21 September 2020.
Article type: Review article.

1. Introduction by gallium or of selenium by sulfur to form Cu(In,Ga)(S,Se)2.

Due to rising energy demands, depletion of fossil fuel, and The efficiencies by using this material have been achieved
environmental pollution, researchers are searchingthe new era higher than 19%. CISe is a member of the I-III-VI2 group of
for energy conversion devices, which give high efficiency. semiconductors and exists in the chalcopyrite phase.[1-6]CISe is
One alternative for this purpose is photovoltaic (solar energy a vital material to solar cells because of its high absorption
converted into electrical energy). Solar cell devices are easy to coefficient (105 cm-1) and comparable band gap (1.05 eV) in
be installed and used and have prolonged operational lifetimes, the solar spectrum, which makes CISe as potential candidates
which avoid the need for continuous maintenance. One of the for use as an absorber layer in solar cells. Due to its optical
main difficulties for solar cell devices is that the price of the properties, this material allows the use of thin films instead of
electricity (cost per watt) produced by solar cell devices is not thick slices of bulk silicon. In this way, we can reduce the
yet reasonable. The problem related to the cost can be reduced consumption of materials. CISe and related chalcopyrite
by either using a high-efficiency device or minimizing the compounds have attracted considerable interests for the thin-
production costs of solar cell modules. The production costs film photovoltaic device to achieve a high conversion
will be minimized with increasing the production volume. To efficiency of about 20% based on Ga containing absorber layer
solve this problem, researcher is finding some low-cost (CIGS).[7] Over the past decade, research into the design of
alternative materials, which are useful for photovoltaic. CISe based photovoltaic with unique properties has been
Nowadays, the most promising absorber materials for solar dramatically intensified. The properties of the CISe absorber
cells are CISe-based chalcopyrite materials. The properties of layer are significant in determining the efficiency of resulting
materials can be varied by doping some material like indium solar cells. Improved performance may also be achieved by
alloying CISe with one of several related compounds, for
1Advanced Physics Laboratory, Department of Physics, Savitribai
example, CuGaSe2, to increase the 1.0 eV bandgap of the CISe
Phule Pune University Pune - 411007, Maharashtra India
device. The crystalline silicon solar cells show high
2D. Y. Patil University, Kolhapur- 416006, Maharashtra, India. production costs of (5 $/W), which are compensated by their
* E-mail: pathan@physics.unipune.ac.in (H.M. Pathan)
higher efficiencies. The efficiency of a small area crystalline

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Si solar cell is above 25% and has been recorded.[8] However, of CISethin films have reported slow-temperature methods
the cost involved in the fabrication of such single-crystalline that give good quality thin films, and these are reviewed below.
silicon-based solar cells still eludes large scale productions. Table 1. Physical properties of CISe thinfilms.[18-25]
This leads researchers worldwide to study thin-film solar cells
based on chalcogenide materials. The inclusion of the Sr.
Property
No.
nanocrystalline materials in photovoltaic devices has been 1. Structural
proposed to improve the incident photon to current 1.1 Crystalline: Tetragonal
efficiency.[9] Most of the researchers are looking forward to (Chalcopyrite).
new approaches, such as the use of nanotechnology to improve 1.2 Lattice constant: a = b 5.782 Å
c 11.620 Å
the device performance. [10-12] Impurities found in CIGS and its 1.3 Space group: 142d-D122d
alloys are beneficial for solar cell operation. CISe [13]

semiconductor is a crucial material as an absorber layer and 2. Optical

offers an advantage of low-cost flexible thin-film solar cells. [14] 2.1 Direct band gap: 1.05 eV
CISe thin films are essential semiconductor materials for solar
cell applications due to their properties such as chemical 2.2 Absorption coefficient, α 105 cm-1
2.3 Rate of variation of bandgap -1.1 x 10 -5 eV K-1
stability, direct bandgap, and high optical absorption.[15] with temperature (dEg/dT)
CuInSe2-based solar cells show long-term stability and the 2.4 Refractive index, n, at 0.546 µm 2.950
highest conversion efficiencies of all thin-film solar cells 2.5 Extinction coefficient, K at 0.647
approximately 19%.[16, 17] 0.546 µm
This review will outline the current status of research 3. Electrical
characterizing the production and properties of thin-film 3.1 Electron affinity, χ 4.30 eV
3.2 Effective density states at the 1019 cm-3
polycrystalline CISeand solar cells based on CISe. In the valence band edge Na
following sections, the most successful chemical methods for 3.3 Minority carrier life time τp 10-10 s
thin-film CISedeposition, the properties, and the performance 3.4 Minority carrier mobility at 300 320 cm2 V-1S-1
of CISebased solar cells are summarized. In the synthesis, the K, µg
3.5 Effective mass of electron (n 0.092
section highlights various ranges of synthesis parameters of type)
CISe materials. The properties section describes the structural, 3.6 Effective mass of hole (p type) 0.71
optical, and electrical properties of the films. The application 3.7 Activation energy 0.18 eV
section analyzes the properties of CISe materials employed in 3.8 Electrical resistivity
1) Cu rich 0.001 Ω cm
current solar cells. The physical properties of bulk CISe are 2) In rich 100 Ω cm
tabulated in Table1. -3
4. Molecular weight 336.28 g cm
5. Density (D) 5.77 g/cc
6. Color Gray
7. Debye temperature 221.9 K.
8. Compressibility 1.4 x 10-11 m2 N-1
9. Melting point 1260°K
10. Thermal expansion coefficient, 11.0 x 10-6 k-1
perpendicular αa
parallel αc 8.4 x 10 -6 K-1
11. Thermal conductivity 0.086 W cm-1 K-1.
12. Specific heat:
C1 -7.67 x 10-4 K -1
C2 4.06 x 10 -6 K -1
C3 4.3 x 10 -9 K -1
13. Low-frequency dielectric constant k 13.6
Fig. 1 Chemical bath deposition system schematics. High-frequency dielectric constant εr 8.1

14. Bohr exciton radius (RB) 10.6 nm

2. Chemical synthesis of CISe thin films
A wide variety of techniques have been used to fabricate CISe 15. Tetragonal eistortion constant 1.004
thin films including chemical bath deposition (CBD),
electrodeposition (ED),[26-39] successive ioniclayer adsorption 2.1 Chemical bath deposition (CBD)
and reaction (SILAR), spray pyrolysis(SP), three-source CBD method is based on a chemical reaction between the
evaporation,[40-48]laser annealing,[49-50]flash evaporation,[51-53] constituent ions. The advantage of this method is low cost and
spray pyrolysis,[54-59] sputtering,[60-69] liquid phase epitaxy,[70- required simple equipment. Precipitation occurs when the
71]electrodeposition,[72-76] screen printing,[77-78]and selenization ionic product exceeds the solubility product (Ks) of the
of metal layers.[79-81]Only chemical methods for the preparation compound to be deposited. Fig. 1 shows the graphical

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representation of the chemical bath deposition technique. The formula (10.84 nm) and Hall-Williamsons relation (9.95 nm).
heterogeneous (film on the substrate) and homogeneous The microtopography thin films studiedby optical microscope
(precipitation in the solution) growth of the films depends on and SEM techniques clearly showed that the film deposition is
the supersaturation ratio. Heterogeneous growth can be uniform and the film covers the entire substrate surface. The
controlled at low supersaturation.[82] Sodium selenosulfate analysis of the recorded AFM 2D image of the thin film
(Na2SeSO3) was used as the selenium precursor in CISe[83-84] surface showed spherical grains having coalescence between
and CIGS [85] thin films prepared by CBD. Garg et al.[84] them. The 3D AFM image showed spike-like growth on the
prepared CISe films at 40◦C using cationic precursors such as film surface. The obtained direct optical bandgap energy from
Cu(NH3)2+4 and citrate-complexed In3+ions. The open circuit UV–vis–NIR spectroscopy is 1.39 eV. Hall effect
voltage (VOC)foran n-Si/p-CISeheterojunction was measured measurement analysis confirmed the semiconducting and p-
to be about 0.3 V after the post-annealing of the CISe film at type nature of the as-deposited CISe thin films.
520◦C in air. Bhattacharya et. al.[83] used solutions containing The advantages of the CBD method are: 1. CBD does not
Cu(NO3)2,In(SO3NH2)3, Ga(NO3)3, Na2SeSO3, tri- require sophisticated instrumentation. 2. Electrical
ethanolamine, NH4OH, and/or NaOH for the preparation of conductivity of the substrate materials is not an important
Cu rich CIGS film. These films were used as absorbers in solar criterion. 3. It is applicable for large area deposition. 4. The
cells that showedan efficiency of 7.3%.[85] Several review process is slow that facilitates a better orientation of
articles discussing the status of CBD have appeared in the crystallites with improved grain structures. 5. As very dilute
literature. The preparation parameters such as pH, deposition solutions are used in the process, the method offers minimum
time, and deposition temperature have been studied to obtain toxicity and occupational hazards. The disadvantages of the
good quality CISe films. The complexing agents are used to CBD method are: 1. Wastage of solution after every deposition.
increase the reaction rate of the solution. Hankare et al. 2. Proper substrate is needed to have good adherents.
prepared a CISe film by using tartaric acid as a complexing
agent.[86] In the reaction bath, Cu+ and In3+ were complexed 2.2 Chemical electro-deposition (CED)
with tartaric acid in the form of the water-soluble tartrate CED is a three-electrode system, namely cathode, anode, and
complex, which controls the metal ion concentration. The a reference electrode. The most commonly used reference
dissociation of sodium selenosulphate, as well as tartrate electrodes are Ag/AgCl and calomel electrode. Fig. 2 shows
complex in alkaline medium, takes place at room temperature. the schematic diagram of chemical deposition. This method is
The process is controlled by the slow release of Cu+, In3+, and widely used in the electronics industry to depositing
Se2- ions in the solution. The hydrazine hydrate acts as a conducting and magnetic layers. The CED of CISe is cost-
complementary complexant, which improves the compactness effective, time-saving, and adequate for safety concerns. It is
and adherence of the film. proved to be a promising way to prepare CISe films.
The CISe micrograph shows a compact structure Electrodeposited copper is now the material of choice for
composed of a single type of small, densely packed interconnects in the ultra largescale integrated circuit. The
microcrystal. The grains are well defined, spherical, and of main advantage of this method is to control the sample
almost similar size. The annealed samples showed an composition.
improvement in grain size. The average crystallite size of the
annealed CISe thin-film was found to be 331 Å. The CBD
method is useful to deposit binary, ternary as well as
quaternary films. By using this method, many researchers
prepared different morphologies of the CISe films. Bhari et al.
showed the granular nature of the CISefilms.[87] The solution
growth technique is used to deposit the CISe film on a glass
substrate. The process involves the reaction of Cu+ with In3+
and Se2- ions in deionized water solution. The temperature of
the solution was held at 60 ºC for about 2 hr and uniform CISe
films were obtained on a glass substrate. The preparative
parameter of this method areshown in Table 2. For example,
Chauhan et al.[88] deposited CISe films by CBD using cupric
chloride dihydrate, indium(III) chloride, anhydrous elemental
selenium, triethanolamine, sodium sulfite, and hydrochloric
acid. All the prepared films have tetragonal unit cell structure
with lattice parameter a and c to be 5.782 and 11.621 Å, Fig. 2 Chemical electrodeposition system schematics.
respectively and the crystallite size estimated by Scherrer's

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Table 2. The preparative parameter for the deposition of CISe using CED.
Subsrate &
Sr. No. Precursors Results Ref.
Temp. (°C)
1 0.040 M CuCl2, 0.008 M Ti Polycrystalline [116]
InCl3, 0.008M H2SeO3. R.T.
(pH ~ 1.5)
2 10 mM CuSO4, 25 mM Ti The as-deposited films deposited between 0 to –0.6 V (SCE) showed [126]
In2(SO4)3, 30 mM SeO2 50 - 55 the XRD reflection of CISe and Cu3Se2where as only those of CISe
(pH ~ 1) were found for films deposited at - 0.8 eV.
3 5 mM CuCl2, 5 mM InCl3, SnO2 Poor adherent films were deposited at -0.7 eV or more potential due [128]
10 mM SeO2, (pH ~ 1.5) R.T. to H2 evolution. The low conversion efficiency of 1.5 % at0.95 Cu/In
ratio
4 3.7 mM CuCl2, Ti binary phases of In6Se7 together with CISe. [127]
22 mM InCl3, 3.6 M SeO2, R.T. rough surface morphology.
(pH ~ 1.5 ).
6. 0.018 M In3+, 0.0018 M Cu+ , SnO2: F chalcopyrite phase [130]
0.025 M SeO2, 0.006 V % R.T.
TEA, 0.007 V % NH3.
(pH ~ 1).
7. 3 mM CuSO4, 6 mM In2(S04)3, Ti The deposition rate increase, as well as the current efficiency [131]
5 mM SeO2, 0.4 M C6H8O7, R.T. increase, but the film morphology did not change.
(pH ~ 1.7).
8. 5-10 mM CuSO4 ,10-20mM Ni/ Ti The formation of smooth layers of the crystalline compound was [132]
In2(SO4)3,10-20mM SeO2, R.T. correlated with a plateau on the polarization curve.
60-80mM K2SO4,0.8mM Films deposited outside the potential range corresponding to the
Na3C6H5O7, (pH ~ 1 ). plateau had poor crystallinity.
9. 3 mM Cu (NO3), 3 mM InCl3,5 Mo The currents corresponding to the reduction of Se4+ to Se on CISe, [133]
mM SeO2,0.4 M C6H8O7, R.T. was smaller than on Mo which was attributed to the formation of the
(pH~ 2.0) insulating film. The effect of the substrate found in the
electrochemical reaction.
10. 3 mM CuSO4,3 mM Mo XRD patterns of In-rich films did not show the characteristics of [134]
In2(SO4)3,5 mM SeO2, R.T. chalcopyrite reflections but only those common to chalcopyrite and
0.4 M C6H8O7 sphalerite phase. No evidence of secondary phases was seen when
(pH~ 1.7) the deposition potential was between -0.5 and -0.8 V whereas the
film deposited at - 0.4 V showed the peaks of Cu2Se after annealing
200-600oC. The surfaces of the CISe films were found to be rich.

12 2.75 mM CuCl2,2.55 mM Ti Chalcopyrite phase [129]

In2SO4,3 mM SeO2,4 M R.T.
KSCN (pH ~ 5)
13 CuSO4, In2(SO4)3, Gr. Annealing under Ar at or above 400 0C for 15 min caused the loss [135]
SeO2.(pH ~ 1) R.T of excess Se and improved the surface morphology.
14 0.73 mM CuCl, Mo Amorphous films; p-type, [136]
5.27 mM InCl3, R.T. high carrier concentration of 3.63 x 1020 cm-3open-circuit voltage
0.9 mM SeO2(pH~ 1) 0.188 V
short circuit density 0.056 mA cm-2
15 CuCl, InCl3, Na2SeSO3, G Chalcopyrite. [137]
NH4OH, C6H8O7. R.T. Voc = 0.165.
(pH ~ 9) Jsc< 1 mA cm-2.
16 0.012 M CuCl2, G Electrodeposited CISe thin films were characterized by AES depth [138]
0.025 M InCl3, 24 profiling to study the concentration gradient of the element present
0.025M H2SeO3, in the film.
(pH~ 1.5 )
17 3 mM CuSO4,3 mM In2(SO4)3, Mo After heat treatment of the sample produces elemental selenium loss [98]
5 mM SeO2,0.4 M C6H8O7. R.T. has been detected together with an enhancement of the allowed
direct optical transition.

18. 5 mM CuCl2, 10 mM InCl3, Pl Here 3D TiO2/CISe nano-composite solar cell obtained. Current [139]
5 mM SeO2, HCl, R.T. studies focus on introducing a buffer layer and on rapid thermal
(pH~ 1.5–2.5) annealing in S.

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19 CuSO4, In2(SO4)3, ITO Hybrid PV structures based on polycrystalline photo absorber [140]
SeO2, R.T. CISe& electrically conductive polypyrrole (PPY) were prepared.
20. 1 mM CuCl,5 mM InCl3, Mo & Pl The copper content in the solution increase with the increasing bath [141]
1 mM SeO2,3.5 M KSCN 20-80 temperature. Amorphous nature with small grains size observed in
(pH~ 4.0) XRD without annealing.
21 5-10 mM CuCl2,22 mM InCl3, ITO TEA has added to the solution as a complexing agent to improve the [142]
22 mM SeO2,1.0 M HCl, R.T. crystallinity and uniformity of the layer.
TEA (pH~ 2.0)
22 2.56 mM CuCl2,4.80 mM SnO2 Multiple phases [144]
InCl3,4.47 SeCl2,0.20 LiCl. 150
23 CuSO4.7H2O, In2(SO4)3, ITO, The effect of the concentration of indium ions in the electrolyte on [107]
Na2SeO3,0.05 M H2SO4, 75 the currents of the cathodic and anodic peaks was studied with the
0.45 M Na2SO4. concentration of indium ions. The composition of the compound
formed was confirmed by the X-ray phase and electron microprobe
analyses. Photosensitivity was found, with the maximum short
circuit current 6 mA and an open circuit potential of 0.4 V.
24 3mM Cu(NO3)2, ITO, Al, XRD shows the amorphous nature of all the films. An additional [122]
3mM In(NO3)2, steel. phase attributed to the In2O3is was also detected. SEM reveals that
5mMSeO2, HNO3, R.T. the CISe film on aluminum shows particles of great size with a more
NaOH. (pH ~ 8.5) remarkable cauliflower appearance. An Eg of 1.09 eV was
determined which become p-type semiconductor, appropriate
material for photovoltaic application.
25 10 mM CuSO4, Ti chalcopyrite phase [129]
25 mM In2(SO4)3, 30 mM 50-55 exhibited poor surface morphologies.
SeO2.(pH~ 1)
26 0.005 M CuCl2, 0.005 M Ti Chalcopyrite structure (113), (220), and (117). XPS shows the [121]
InCl3,0.01 M SeO2, R. T. chemical and stoichiometric change occurring at the top surface
(pH – 1.5) layers within the probing depth of 30 Å.
Structure: cauliflower type.

27 2.56 mM CuCl2 ,4.80 mM FTO From XRD that the material comprised Cu-Se binaries and CISe [120]
InCl3, 4.47 mM SeCl4, 0.20 150 phases. XRF identified increasing indium content at more negative
mM LiCl deposition voltages.
29 1.14-4.55 mM CuCl2, 3.75 ITO the bulk concentration of Cu and Se and deposition potentials on the [118]
mM In2(SO4)3, 6.89-13.78 mM R.T. stoichiometric properties were discussed.
H2SeO3,0.7 M LiCl,
1 mM BTA (pH - 3)
30 2 mM CuCl2, 0.6 mM InCl3, 4 ITO The result showed that the reduction of Cu2+ to Cu+ at one potential [145]
mM SeO2, 15 mM C6H5 R.T. point of -800 mV In XRD, the film shows 112, 312, 220 peaks.
Na3O7, CitNa, NaOH, HCl.
(pH - 6.5-7)
31 1mM CuCl2, 3mM InCl3, TiO2 A cross-section thickness of CISethat was found at 3.16 µm. The [125]
1.7 mM SeO2.(pH - 2) R.T. bandgap values of CISe was found to be 1.04 eV.

32 3 mM CuCl2, 6mM InCl3, TiO2 chalcopyrite phase. [145]

5mM SeO2,0.4 M Sodium R.T. The optical band gap lies between 1.02 and 1.45 eV.
citrate. HCl, NaOH (pH: 4-6)
33 1.0 mM CuSO4, 3.3 mM ITO The photovoltaic characteristics were measured were, [147-148]
In2SO4, 3.3 mM SeO2. R.T. Jsc = 0.56 mA/cm2, Voc= 31.3 mV. Vbi= 2.15 eV,
ND= 3.67 x 1017 cm-3
34 1mM CuCl2, 5mM InCl3, Plastic The bandgap of the CISe film was about 1.18 eV. [119]
1mM SeO2,1M TEA, R.T.
0.1 Na-Citrate, HCl
(pH = 1.65)

The stoichiometric relation between the Cu, In, and Se chlorides were used in CED. In this method, the Na2SeSO3is
atom is directly related to the CED conditions and dissolved into a mildly acidic solution in the form of HSeO3
concentrations. CED of CISe based thin films is commonly and sodium sulfite (Na2SO3).[89] According to the Nernst
carried out by using an aqueous solution that contains a simple equation, the electrode potentials for selenium and copper will
compound of Cu+ or Cu2+ and In3+ ions. Mostly sulfates or lead to the deposition of indium. This problem has been

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overcome by using a complexing agent (like citric acid, tri- for the preparation of CISe film. In CED, Cu2+ compounds are
ethanolamine, CN-, etc) to shift the copper deposition potential used more frequently than Cu+compounds because of the
in the negative direction close to the In deposition potential. limited solubility and instability of Cu+ions in aqueous
Cathodic CED of CISe is based on the co-reduction of Cu2+/Cu, solutions. The Se precursor SeO2is dissolved into mildly
In3+/In, and the reduction of HSeO2- species.[90-91] The available acidic solutions in the form of HSeO3−.[116] Sometimes, a
free energy from compound formation results in a shift of the supporting electrolyte as sulfate (K2SO4) or chlorides was
metal deposition potentials to positive values (relative to the used.[117] Beyhan et al. studied the effect of the complexing
standard potentials E0). When the external power supply agent on the stoichiometric ratio of the CISe thin films.[118] The
drives a current through the cell, metal ions are reduced to solution contains CuCl2, In2(SO4)3, LiCl, benzotriazole (BTA)
metal atoms at one of the electrode (cathode) and chalcogen dissolved in pH buffer (pH -3) for the preparation of CISe
ions to the other electrode (anode). film.This film was prepared by using a three-electrode such as
According to the Nernst equations: Reaction (E0vs SHE) counter electrode (Pt gauze), reference electrode (SCE), and
ITO substrate ITO at room temperature without stirring the
Cu2+(aq.) + 2e-→ Cu (S) 0.337 eV (1)
electrolyte solution. The deposition potential and
In3+ (aq.) + 3e-→ In (s) -0.342 eV (2)
concentration of the Cu and Se can affect the surface
HSeO + 4e + 4H + OH → Se (s) + 3H2O 0.741 eV (3)
2- - + -
composition of the films. The Cu gives a complex reaction
The electrode potentials of selenium and copper are more with BTA for the enhancement of the reduction reaction rate.
positive than that of indium. The simultaneous deposition of A uniform and transparent film with good stoichiometry
Cu, In and Se, adjustment of pH, and concentration of (In1Cu1Se1.8) was obtained under -0.55 V/SCE at pH 3. Huang
electrolyte can make the potential close to each other. If the et al. prepared CISe film on flexible (Au coated plastic)
cathode potential is made more negative, the rate of reaction substrate by the CED method.[119] They also studied the effect
increases and if it is made more positive, the reverse reaction of the complexing agent i.e. TEA, Na-citrate on the quality of
will be possible. the films. The buffer agent TEA was used to suppress the
reduction of copper ions during the growth process. Also, the
Cu (solid)→ Cu2+ + 2e - and In (solid) →In 3+ + 3e-(4)
concentration of Na citrate added into the bath was varied from
The potential, at which the rates of the forward and reverse 0 to 0.2 M during the growth process to avoid the pH variation.
reaction are equal, is called equilibrium potential. It depends The CISe filmswere formed on the plastic substrates with
on the concentration of Cu2+, In3+, and Se2- ions in the different concentrations of TEA in bath solution. The dense
electrolyte which is denoted by M. distribution on the surface of the CISe film was observed. The
Eeq = E01 + (KT/ne) (ln M ) (5) sparse distribution and cloud-like precipitation on the surface
01
where E is the Formal potential and M is the concentration of of the films are shown in this result. This result is due to the
the ions. high concentration of TEA, which causes a colloid state in the
The rate of metal deposition is controlled by the electrolyte. The precipitation of the colloid state electrolyte
overpotential (V) given by: adheres to the surface of the substrate during co-deposition.
V = Eeq – E (6) Thus the quality of the film is degraded. From the image
where E is the potential applied to the electrode. observation, it was concluded that the 1M TEA optimal
The process of decomposition of an electrolyte concentration is controlled.
depends on passing an electric current through its aqueous Sodium citrate was added into the growth solution to
solution. The potential ranges of various compounds depend control the pH value of the solution. In the SEM micrograph
on various factors such as total conductivity of the solution, of the CISe film with various concentrations of the Na-Citrate,
cathode surface area (ohmic drops), electrolyte temperature,[91] the white and column-like precipitation was observed on the
etc. The complexing agent used in the solution shifts the surface of the CISe film. This indicates the hydrogen evolution,
reduction potential of the Cu and In ions close together and which produces indium hydroxide precipitations on the
improves the quality of the film. The results show that single surface of the film. This precipitation fully disappeared when
phase CuInSe2 can be obtained by suitably controlling 0.1 M Na-citrate was added in the bath. The quality of CISe
deposition potential and heat treatment. The estimated number film can be improved by adding 0.1 M Na-Citrate. The
of electrons transferred for the overall reaction of CuInSe2 morphology and composition of CISe films depend on the
deposition was 13 [92] The complexing agents including citric deposition voltage. Wellings et al. [120] discussed the
acid, ammonia, tri-ethanolamine, ethylene-di-mine, ethylene- morphology variation of the films concerning different
di-amine tetra-acetic acid (EDTA), thiocyanate, etc. are used deposition voltages. They prepared CISe film from ethylene
in CED. One-step CED of *** (CIS)is mostly carried out glycol at 150 oC by the ED method. Although the films were
potentiostatically at RT by using sulfates copper selenides deposited at 150 oC, no noticeable improvement of the CISe
obtained are depending on the solution composition and the was observed, suggesting the growth from aqueous media at
diffusion conditions[93-104] or chlorides,[105-114] room temperature to be preferable. SEM was carried out to the
galvanostatic [106,107,115] and pulsed CED [102,113,114] have been used layer to investigate the surface morphology. The presence of

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individual crystallites 10-20 nm in size is observed. Different process of the film can be divided into three well-separated
morphologies were compared to the film deposited at -0.80 V stages. In the first stage (up to 100 nm), the formation of the
vs SCE. Larger crystallites were formed around 0.5 – 1.0 µm. Cu rich binary phase (Cu2Se). This implies that the nucleation
The SEM image of the layer deposited at -1.00 V vs SCE process is mostly controlled by the Cu rich binary than the
shows a crystallite size of 0.2 to 0.5 µm with an additional CISe chalcopyrite. Cu concentration is more as compared to
surface object around 1.0 µm.Dharmadasa et al. prepared 25 the In concentration. But, in the second stage (after 100 nm),
samples of CISe films using a single electrolyte by the ED the In concentration starts to grow as well as the Cu
technique.[121] A typical electrolyte can be formed by using concentration decreases. Se concentration is considered
0.001 M CuSO4, 0.004 M In2(SO4)3, and 0.008 M almost constant throughout the entire layer. Indium starts to
H2SeO3,which are dissolved in de-ionized water. The uniform participate in the overall process when the concentration of Se
and well adhesive layers are produced for some voltage is significantly higher, and then the formation of ordered
regions. The layers grown are disordered and dissolved in vacancy compound (OVC) and chalcopyrite phase starts.
the electrolyte at voltages ~ 1.90 V and (2.53 – 2.56) V. This During the first stage, the contribution of Cu2Se diminishes
indicates that these voltages do not help grow stable layers for with time, and the OVC phase slowly increases and the
the fabrication of solar cell. The surface morphologies of layer elemental Se decreases at the same time. In the third stage
from 2.03, 2.46, and 2.70V were studied by using AFM images. (after 800 nm), quasi-steady state occurrs and is maintained up
At these three voltages, the nanoparticles were grown to the final growth steps. Before the end of the third stage,
spherical. Araujo et al. deposited CISe films on different CuSe binary phase starts to dominate the phase’s formation.
substrates like ITO, Al, and Steel, etc. from the alkaline But the OVC and the free elemental Se decreases. The Cu2Se
medium by using the CED technique.[122] From SEM images, binary seems to be thermally sensitive, decomposing at 200 ºC,
a uniform deposition with a compact surface on ITO substrates being the key factor for the OVC vanishing, and the formation
can be observed. The structure exhibits multi nuclei with of the CISe chalcopyrite phase. The Raman spectra before
uniform size and is cauliflower-shaped at the steel substrate. thermal treatment (BTT)and after thermal treatment (ATT)
This was a more compact film. The particles show a great size ofCISe film show that the OVC signal decreases and the CISe
with a more remarkable cauliflower appearance on an Al signal increases in ATT. Valdeset al. have prepared
substrate. TiO2/In2Se3/CISe heterojunction by using CED and chemical
The structural properties of the CISe film depend on the SP technique.[125] In this work, a dense TiO2 layer is deposited
post-deposition treatments. De Silva et al.[123] prepared CISe by the SP method. After that, In2Se3 was electrodeposited on
films by CED technique at room temperature. They discussed TiO2. Lastly, CISe was electrodeposited on the In2Se3 film.
the variation of structural properties of the film with changing The In2Se3 acting as a buffer layer was used to improve the
the annealing temperature in air and argon media. In XRD, if conversion efficiency. In2Se3 thin films were electrodeposited
the samples were annealed at a temperature above 350 ºC in in between the TiO2/CISe p-n heterojunction to block the
air media, there was a drop of CISe peak (115) intensity and electron backflow and lower the interfacial recombination
some additional peaks appeared, which indicates the produced after the illumination. This film was annealed in Se
formation of other compounds such as In2O3 and CuO. The atmosphere to improve the crystallinity of the film. The Cu
formation of CISe was strong when annealed at 350 ºC but rich and Se rich phases were removed after etching the films
completely dissociates at temperature 500 ºC. But at argon in a 0.5 M KCN aqueous solution. The In2Se3 films are
media, the CISe peak can be observed even after annealing at homogeneous and formed by nanosized particles. A cross-
500ºC without forming the secondary phase. They also section view gives the thickness of the layers. The average
showed that the deposition potential influences the atomic value results in 0.47 µm for the thickness of the In2Se3
composition of In and Se present in the film. The indium deposited during 15 min at a -0.8 V and 3.16 µm for CISe
content gradually increases while the composition of Se deposited for 60 min. The advantages of electrodeposition are:
gradually decreases when the negative values of the deposition 1. It makes it possible to grow uniform films on different
potential are increased. There was no noticeable variation in substrates and over large and/or irregular areas, from cm2 to
the Cu concentration with an increase in deposition potential. m2. 2. It is particularly suited to the fabrication of
SEM images show the cauliflower type features of various heterojunctions simply through a change in the deposition
sizes of the particles up to 6 µm. CISe films were annealed at electrolyte. The disadvantages of electrodeposition are:1.Not
600 ºC and cracks were observed, visible as thin lines. applicable for the insulating substrate. 2. Poor thickness
Saucedo et al. studied the phase evolution in the growth of uniformity on complex components
CISe film on polycrystalline MO by CED technique.[124] The
solution contains 1 mM CuSO4, 6 mM In2(SO4)3, 1.7mM SeO2, 2.3 Successive ionic layer adsorption and reaction method
and a supporting sulfate electrolyte. The deposition potential (SILAR)
was fixed -0.9V/MSE and the charge density was varied up to Thin-film deposition by this method has recently attracted
5 C.cm2 to control the thickness from 100 to 4350 nm. This attention among many researchers because the method offers
experiment was performed at room temperature. The growth many advantages over the more established synthetic routes to

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obtain semiconductor materials. SILAR is based on the

immersion of the substrate into separately placed cationic and
anionic precursors. Fig. 3 shows the graphical representation
of the SILAR technique. The growth model is the basic
difference between CBD and SILAR. In CBD all the
precursors are present at the same time in the reaction vessel,
whereas in the SILAR, the substrate is treated separately with
each precursor and rinsing separates these treatments. There
are different preparative parameters of the SILAR method,
such as the composition of precursor, pH of the cationic and
anionic precursor solutions, reaction and rinsing time,
deposition temperature, dip cycle, etc. These parameters were
optimized to prepare p-type, uniform, pin-hole free, and
adherent CISe thin films with maximum thickness.[149] The
SILAR is based on a sequential reaction at the substrate
surface. Rinsing follows each reaction, which enables
heterogeneous reaction between the solid phase and solvated
ions in the solution.

By repeating these cycles, a thin layer of the material can

be grown. The graphical sequence gives the proper idea of the
formation of a good quality thin film by using the SILAR
method. The flow chart gives the exact steps of the deposition
of CISe by using SILAR methods.
Pathan et al. firstly used M-CBD to prepare CISe film at
room temperature, studied the structural, morphological, and
electrical properties of the film.[150] Recently, most of the
researchers reported the effect of different cationic precursor
solutions on the formation of CISe thin films by this method.
Fig. 3. SILAR synthesis system schematics. The film thickness increases with an increase in concentration
This method is mainly based on the adsorption and reaction and deposition cycle. SEM images of such films were found
of the ions from the solution on the substrate. In addition to to be smooth and uniform. Yang et al. prepared CISe thin films
this rinsing, the substrate is done between every immersion by using this technique with different deposition temperatures
with deionized water to avoid homogeneous precipitation in (Td).[151] The solution bath contains CuCl2, InCl3, TEAH3,
the solution. The adsorption takes place between ions and the citrate, Na2SeSO3, HCl, and NH4OH.The deposition of CISe
surface of the substrates due to Vander Waal forces of films was carried out at different temperatures such as30, 50,
attraction. Rinsing time is selected such that there is no 70, and 90 ºC, respectively.To achieve the required thickness,
formation of precipitation in the cationic and anionic precursor. all stages are repeated from 20 to 100 times. The surface
The thickness of the film is controlled directly by the number roughness of CISe films depends on dip cycle times and
of deposition cycle and deposition temperature. When the deposition temperature. The morphology the film varys with
substrate is immersed in the copper and indium containing increasing temperature. The thickness of the films increases
solution with a complexing agent, then Cu2+ and In3+ ions are from 180 nm at 30 ºC to 1000 nm at 90 ºC, and this implys that
adsorbed on the surface of the substrate. TEA is the most the growth rate of the film is varied with Td. They also
popular complexing agent.[9] After immersion of the substrate explained the variation of the morphology of the film by
in a solution containing Se2- ions, reaction corresponding to increasing the dipping cycle. At 20 dip cycles, the surface of
CISe takes place. the film is very smooth and uniform. At 40 dip cycles, grain
Cu + + In 3+ + Se2- → CISe (7) size becomes larger. With further increasing the dip cycle,
In general, the following sequence of SILAR technique isolated islands increase on the film surface and the area of
gives good quality thin films. these islands successively increases (dip cycle = 60, 80, 100,
Td= 30ºC). This non-uniform growth is due to the
inhomogeneous nucleation growth.

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Table 3. Preparative parameters for the deposition of CISe thin films using SILAR method.

Sr. Precursors Substrate & Results Reference

No. Temp. (°C)
1 0.12 M CuSO4, 0.08 In2(SO4)3, G The electrical resistivity 102- 103 Ω cm [151]
0.05 M Na2SeSO3 TEA. 27
2 0.12 M CuSO4, G & FTO The XRD & HRTEM studies showed the nanocrystalline [152]
0.08 M In2( SO4)3, 0.1M 27 CISe.
Na2SeSO3,
3 CuCl2.2H2O, InCl3.4H2O, G Accelerated growth rate by deposition time could reduce [158]
TEA, Na3C6H5O7, 30-90 the dip cycle time for required film thickness, which
Na2SO3, Se, HCl ,NH4OH improved the quality of film morphology
(pH=8)
4 CuCl3, InCl3, TEA, Na2SeSO3, G The annealed samples show crystallinity.SEM results [159]
Na3C6H5O7. 70 in shows smooth surface

5 CuCl2, InCl3, TEAH3, CitNa, G The XRD displayed the main reflection peaks at 26.70, [157]
HCl, NH4OH, Na2SeSO3, CH3- R.T. 44.30, 52.40have corresponded to the CISe planes (112),
(CH2)11,-C6H4-SO3Na. (220)/(204), and (312)/(116) resp. The Cu, In and Se
element analysis of rod crystals detected by EDS is
23.81%, 22.72%, and 53.47% resp, close to CISe
stoichiometry of 1:1:2

and SDBS. Rod crystals appeared on the surface of the CISe

When Td=70 ºC, the morphology of CISe film has a similar
film after adding SDBS to the solution. SDBS was added into
trend, but isolated islands seem at fewer times of dip cycle.
a cationic precursor solution from 0 to 0.01 mol/L. This
Furthermore, the grain size of these films prepared at 70 ºC is
process was carried out at 70 ºC. Without SDBS, the
more than 30 ºC under the same dip cycle times.
morphologies of the annealed CISe film were clear and
Pathan and Lokhande et al. prepared CISe thin films by
consisted of granular grains with slightly agglomerate
using the M-CBD technique at room temperature.[152] A
compared with the as-grown films. However, with SDBS, the
solution contained copper sulfate, indium sulfate, sodium
rod-like agglomerations, stacked by CuSe and In2Se3,
sulfite, selenium pellets, and tartaric acid. The concentration
appeared on the surface of the film. After annealing, the loose
of anionic precursor (Na2SeO3) was arbitrarily maintained
structure of CISe film could provide high vapor pressure for
constant at 0.05 M with pH-12. They prepared CISe film by
solid–vapor-solid mass transfer growth of rod-type crystals.
using 80 deposition cycles. From highermagnified SEM image
The effect of SDBS on rod crystals growth was studied by
and AFM micrograph, small isolated grains with spongy
changing the amount of SDBS. With the increase of SDBS, the
surface were reported for the Cu rich films. The surface is well
length of CISe rod crystals was increased, but the diameter of
covered with CISe. At the right-hand side of the image, the
the rod changed slightly except several dumpy rods. At low
intensity strip indicates the height of the surface grain along
SDBS contents, a few rods of crystals were formed, but as the
the Z-axis. The grain boundaries are seen. Continuous
SDBS content increases, the size of the rod crystal gets an
arrangements ofclosely packed grains observed the spherical
increase. While SDBS increased to 0.01 mol/L, the length of
grains are visible, which indicates the 3-D growth of the film.
the rod crystal exceeded up to 5 µm. The preparative
Now there are several reports about CISe film with rod/wires
parameters of the SILAR method as shown in Table 3.
with a controllable composition. Mostly, these rods/wires were
Advantages of the SILAR methodare detailed as: 1. SILAR
prepared by solvothermal or vapor-liquid-solid method at a
does not require a target, nor does it require a vacuum at any
very high temperature using extremely high toxic
stage of the process. 2. The deposition rate and the thickness
materials.[153-156]
of the film can be easily controlled over a wide range by
Yang et al. prepared a CISe film using sodium
changing the deposition cycle. Disadvantages of the SILAR
dodecylbenzene sulphonate (SDBS) as a directing agent by
method asre: 1. Expensive autoclaves are needed.2. Safety
SILAR.[157] The solution contained anionic precursor 0.06
issues during the reaction process, and impossibility of
mol/L Na2SeSO3 solution with 8 pH and cationic precursor
observing the reaction process.
CuCl2, TEAH3, InCl3, sodium citrate (CitNa), HCl, NH4OH,

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2.4 Spray pyrolysis (SP) of the round grains for the films with an In/(Cu+In) ratio of
This technique has been one of the major techniques being 0.55, 0.60, 0.67 was observed in the range of 0.1-0.3, 0.3-0.4,
used for the deposition of thin films of a wide variety of and 0.3-0.5 μm, respectively. The round and platelet grains
materials for the past three decades. This technique has also observed on the surface of the film with the In/(Cu+In) ratio
been successfully employed for the formation of were 0.70. It can be easily found that the surface morphologies
superconducting oxide films. In this method, the properties of of the films with in/(Cu + In ≥ 0.72 differ from those of the
the thin films depend on the anion to cation ratio, spray rate, films with in/(Cu+In )≤ 0.70. The composition of the CISe
substrate temperature, carrier gas, droplet size, spray time, the film is plotted in a ternary composition plane.[161] The plots are
concentration of the solution, spray gun nozzle to substrate on the tie line of the Cu2Se-In2Se3 pseudobinary system, which
distance, etc. The main advantages of this method are: 1) It indicates that the valance stoichiometry is preserved. If the
neither requires high-quality substrate nor vacuum at any stage. films contain the In2O3 phase, plots should be on the left side
2) There are no virtual restrictions on the substrate material, of the Cu2Se-In2Se3 tie line. The preparative parameters of the
dimension, or surface profile. 3) The deposition rate and SP method are shown in Table 4.
thickness of the film are easily controllable over a wide range Advantages of spray pyrolysis are: spherical morphology,
by changing the spray parameter and 4) Operates at moderate narrow particle size distribution, compositional homogeneity,
temperatures (100-500 ºC). and high controllability of composition of the obtained
Fig. 4 shows the graphical representation of the spray products. Disadvantages ofspray pyrolysis are not easy to
pyrolysis technique. The spray gun sprays the cationic and scale-up (yield is very low), (2) oxidation of sulfides when
anionic precursor solution on a heated glass substrate. The processed in air atmosphere is possible; (3) there are
deposited film property shows variations with the change of difficulties with determining the growth temperature.
pH value of the spray solution. Excellent controllability of the
film composition can also be achieved by changing the spray
solution composition. It is known that the composition ratio
Cu/In affects not only the electrical properties but also the
structural ones. It was observed that Cu rich films exhibit
chalcopyrite structure with the appearance of the characteristic
XRD lines corresponding to 101, 211, and 301
planesirrespective of the pH value. The In-rich films deposited
at 300 ºC exhibit no XRD lines.[160] However, at 360 ºC, both
In and Cu rich films were found to exhibit the chalcopyrite
structure, independent of pH. Terasako et al. prepared In rich
CISe polycrystalline thin films by this method.[2] The spray
solution containing an aqueous ethanol solution of CuCl2,
InCl3, and N, N, dimethyl selenourea (DMSeU). The substrate
temperature was 360 ºC. The In/ (Cu+In) ratio got varied from
0.5 to 0.83. The pH value was adjusted up to 3.5 by adding
NH4OH.The SEM images were observed for the CISe films
with various in/(Cu+In) ratios grown at 360 ºC. The diameter Fig. 4 Spray pyrolysis deposition system schematics.
Table 4. Preparative parameters for the deposition of CISe thin films using the spray pyrolysis technique.

Substrate &
Sr.No. Precursors Results Ref.
Temp. (°C)
Below 2500C, the peaks decreased in size, whereas above 4000C,
CuCl2, InCl2, G
1. the second phase was generated shown in XRD. Annealing at [161]
N, N, DMSeU. 300-350
5000C shows crystalline nature
CuCl2, InCl3, bandgap (Eg) of 1.02 eV.
G
2. N, N, DMSeU, NH4OH. Film resistivity 10-2 to 105 Ω cm-1 [162]
300-360
(pH ~ 1.9 -4.0) In SEM, porous morphology with rod-like grains
CuCl, InCl3, SnO2
3 The best PEC cell showed a 6.22 % conversion efficiency [122]
CSe (NH2). 350
CuCl2, InCl3,
G
4. N, N, DMSeU. The Eg value increased from 1.22 to 1.36 eV [163]
360-400
(pH ~ 3.5)
CuCl3, TEA,
G The XRD, XPS, and SEM results showed that it was crystallized,
5. InCl3, Na3C6H5O7, [117]
70 smoothly, and distinctly particular.
Na2SeSO3.

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Table 5. Preparative parameters for the deposition of CISe thin films using a hydrothermal technique.
Sr. Precursors Temp.(°C) Results Ref.
No.
1 Acetic acid, Copper powder, 200 SEM images showed particle size between µm to nm. [165]
Indium powderand selenium
powder
2 copper (II) chloride, indium (In), 180 XRD pattern chalcopyrite (tetragonal) structure of synthesized samples. [166]
sulfur (S), selenium (Se) SEMand TEM analyses show that samples were composed of cubes
deionized water with the size of nanometers.

3 CuCl2·2H2O, InCl3,and SeO2 160 The XRD peak corresponding to (112), (204), and (312) crystal planes, [167]
180 respectively. The powders consist of irregular spherical grains with
200 0.2~0.5 μm in diameter
4 Cupric chloride, indium chloride, 150 The crystallinity was found to be higher with a 10 mol ratio of the [168]
sodium selenite, capping agent. While the optical absorption and emission are concerned
ethylenediamine, deionized the 10 EA has higher absorption and emission intensity followed by the
water. 10 EW.

5 Copper foils, indium chloride, 80 The crystallinity and density of the as-synthesized CISe films were [169]
triethanolamine, sodium improved via increasing the selenization temperatures and prolonging
hydroxide the hydrothermal duration. Se2-ions react with copper foils to form the
Cu2-xSe phase at the beginning of the reaction. Indiumions adhere to the
Cu2-xSe surface, owing to the chelation of triethanolamine. In3+ and Se2-
ions then reaction Cu2-xSe to form the In2Se3 phase.

The process of XRD methods observes the crystallographic

2.5 Hydrothermal Method
features of CISe films. This characterization technique is
The hydrothermal method is widely used to prepare
beneficial to determine various properties of the thin films like
nanostructural materials because of its simplicity, high
crystal structure, crystalline orientation, grain size, lattice
efficiency, and low cost. It is the most commonly used method
parameters, lattice strain, and stress, etc. In comparison of
for the preparation of nanomaterials. The hydrothermal
observed inter-planar distance and standard value, CISefilm
technique is becoming one of the most important tools for
has a chalcopyrite tetragonal structure. But some literature
advanced materials processing, particularly owing to its
shows different values, which are comparable to the secondary
advantages in the processing of nanostructural materials for a
phase. It means that thin-film contains some impurities as well
wide variety of technological applications such as electronics,
as some defects.[8] This information was beneficial for the
optoelectronics, catalysis, ceramics, magnetic data storage,
photovoltaic application. Akl et al. studied the effect of Cu/In
biomedical, biophotonics, etc. Hydrothermal can be defined as
ratio as well as substrate temperature on the structural
‘hydros’ meaning water and ‘thermos’ meaning heat. Several
properties of the CISe films.[169] The chemical technique was
methods have been reported on the deposition of CuInSe2 thin
used to prepare polycrystalline CISe films. The XRD pattern
films and nanoparticles such as chemical bath deposition,
of the as-deposited CISe films on a glass substrate at different
magnetron sputtering, flash evaporation, spray pyrolysis as
Cu/In ratios shows an additional line at 24.20, which is
well as thermolysis, photolysis, microwave synthesis,
identified for the Cu2-xSe phase. The Cu2-xSe phase detected at
microwave irradiation, sol-gel, wet chemical, solvothermal
the Cu/In ratio reached 0.96 and more at temperature 548, 573,
and hydrothermal methods. However, the above approaches
and 673 K. The phase of Cu2-xSe disappeared at all substrate
required complicated facilities, high temperatures and some of
temperature for ratio less than 0.96. Moreover, the (112), (204),
them use toxic reagents like organometallic compounds and
and (312) peaks indicate the single phase of CISe having the
hydrogen sulfide (H2S). To avoid these drawbacks,
tetragonal structure. The chalcopyrite phase was obtained for
hydrothermal and solvothermal methods have been widely
the prepared films independent of both the substrate
studied. This method is also particularly suitable for the
temperature and the Cu/In ratio. The intensity of the (112)
growth of large good-quality crystals while maintaining
peak gets concerning the Cu/In ratio at different substrate
control over their composition. The preparative parameters of
temperatures. The profile shape parameter was obtained
the SP method are shown in Table 5. Disadvantages of the
through a pattern decomposition followed by a Voigt function
hydrothermal methodare: (1) the need of expensive autoclaves;
for size strain separation. Voigt function is based on the
(2) safety issues during the reaction process; and (3)
integral breadth of lines used to calculate the crystallite size of
impossibility of observing the reaction process.
the investigated sample. The crystallite size calculated with
different Cu/In ratio at different substrate temperatures results
3. Properties of CISe thin films
in that the crystallite size gets increased by increasing the
3.1 Structural
Cu/In ratio and decreased by increasing the substrate

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temperature. This means that the growth under Cu rich method using nearly neutral electrolytes with sodium citrate
conditions seems favorable to the obtainment of large complex.[173] Voltammograms of CuCl2, InCl3, SeO2 individual
crystallite size. The behavior of this crystallite size in an and mixed solutions with CitNa - complexing agents were
indium rich and copper-rich sample was reported in the measured. The solution bath contained 2 mM CuCl2, 0.6 mM
literature.[170-171] The macro-strain decreases with the raise of InCl3, 4 mM SeO2, and 15 mM sodium citrate, and the pH of
either Cu/In ratio or the substrate temperature which is the electrolyte solution was adjusted by NaOH and HCl. This
expected since the atoms or molecules are ejected from the is a three-electrode system, in which indium tin oxide coated
target source by higher momentum transfer due to its ionic glass (ITO) was used as working electrodes, a large area Pt foil
collisions observed. acted as a counter electrode, and Ag/AgClsat (+222 mV/NHE)
The microstrains were produced due to more power density as a reference electrode. According to the result of
events with higher kinetic energy and mobility, which were voltammograms, the double potentiostatic parameter was
recombined on the substrate surface. The grain size of the film selected as V1=-800 mV for t1=30 s and V2= -1400 mV for
depends on the composition of the film. The grain size t2=60 s, for 5 cycles. As a contrast, some films were also
calculated by using the Debye-Scherer relation (D = 0.9 prepared by the single potentiostatic condition at -800 and -
λ/βCosθ, where β is the full-width half maxima, and λ is the 1400 mV resp.
wavelength of CuKα). Bindu et al. prepared CISe film through FromXRD, clear characteristics peaks of the ITO substrate
a new selenization process.[172] The Cu rich sample showed are observed. When the film was deposited by the single
maximum grain growth (180 Å). As the ratio increases, grain potentiostatic ED (SPSED) method at -800 mV, only Cu2O and
size increases and reaches saturation when the ratio is 1.6. In little CuSe phase appear after annealing and at -1400 mV, InSe
the case of a large ratio, Cu may reduce the stoichiometry of and a small amount In2Se3 phase occurs but no Cu containing
the films, resulting in reduced grain size. The XRD patterns of phase appears. However, (112) peak at 26.60, (204, 220) peaks
the CISe filmswith different Cu/In ratiosshow that as the Cu/In at 44.20, and (116, 312) peaks at 52.30of chalcopyrite CISe
ratio increases, the intensity of all the peaks increases from phase can be observed after annealing by DPED. The
curve c to f, respectively. For film 1.8, the peak intensity diffraction peaks of CuIn alloy and metal indium are observed
decreases, because excess Cu reduces the stoichiometry of the without any selenium containing crystal substance. These
film. The FWHM value of the film corresponds to the (112) detected results illuminate the advantages of the DPED
planes of the respective films obtained from the XRD. method, in which the reduction of Cu2+ to Cu+ at one potential
In the SP technique, the crystal structure of the CISe film point of -800mV as well as of CuIn alloy in the as-deposited
depends on the Cu/In ratio, substrate temperature, and pH of film is responsible for the formation of CISe chalcopyrite. The
the solution. Shirakat et al. prepared the CISe films on glass high resolution XPS spectra in Cu2p3/2, In3d5/2 and Se3d5/2
substrate from the ethanol by chemical SP.[161] Good regions are observed. The binding energy (BE) of Cu2p3/2,
chalcopyrite CISe films with large grains have been grown In3d5/2 and Se3d5/2 is 932.7, 444.6, and 54.8 eV respectivley
using a neutralized spray solution (pH = 4) at the growth after annealing. The corresponding BE values for the as-
temperature of 360 ºC. On the other hand, low values of Ts, deposited films are 932.1, 444.3, and 55.1 eV, respectively.
pH, and Cu/In led to the production of sphalerite films. The BE values of Cu2p3/2 and In3d5/2 for the as-deposited
Ranges of Cu/In and Ts for the production of the chalcopyrite film are slightly less than that of the annealed film, due to the
and the sphalerite phase are summarized for pH values 1.9 and formation of CuIn alloy in the film. But for Se3d5/2, the BE
4.0. From this graph, it can be said that the Cu rich CISe films value is different from that of the annealed film. There is a
tend to have the chalcopyrite structure, whereas the In rich second peak (59.3) appearing on the Se3d5/2 high-resolution
ones tend to have a sphalerite structure containing the In2Se3 curve, which corresponds to the BE value of SeO2. It means
phase. To form the chalcopyrite structure, additional energy is that SeO2 may be deposited on film during the DPED process,
required to order the atoms from the disordered sphalerite which is permitted to be eliminated by de-oxidation of SeO2
form. This is the reason why the activation energy for the in the period of the annealing in the Argonatmosphere.The
chalcopyrite phase formation (Ec) is larger than that for the complexing agent is used to improve the crystallinity of the
sphalerite one (Es). Therefore, the energy gained due to high film. Yamaguchiet al. electrodepositedCISefilm by using tri-
Ts may enhance the production of the chalcopyrite-type film. ethanolamine (TEA) as the complexing agent.[174] The effect of
Wellings et al. deposited CISe film by using ED techniques. concentration of TEA on the formation of the CISe film, the
CISe film prepared from ethylene glycol at 150 ºC.[120] The XRD patterns of CISe films deposited with 0.05, 0.1, and 1.0
following graph shows the composition study of the layer by M of TEA were exhibited.From the XRD patterns, it was
using EDAX techniques. Identified characteristic peaks of found that the crystalline signals of the CISe were less strong,
Cu and Se with small in peak also present for the layer especially the preferred orientation in the (112) plane of the
deposited at -0.080 V vs Se. The EDAX of the film deposited chalcopyrite structure, as the concentration of TEA exceeded
at -0.95 and -1.00 V vs Se were the same, indicating that Cu, 0.1 M. It is believed that the complexing reaction was
In and Se were present in the bulk. Yang et al. prepared case complete with a high concentration of complexing agents and
films by alternating the double-potentiostatic ED(DPED) therefore hindered the deposition of CISe film. The SEM

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images bring to a comparison of the surface grains from the reflectance, optical reflection, and transmission, absorption,
deposited films under different potentials. In the case of -0.6
luminescence, photovoltage, and photoconductivity, bandgap,
V vs Ag/AgCl in the multinuclear, cauliflower-like grains of etc. The optical spectrum reveals that CISe film has a high
absorption coefficient (105 cm -1) and the bandgap energy
the crystalline structure of CISe are observed. The structural
properties of CISe film also depend on the pH of the solution.
range from 1.04 to 1.9 eV. Huang et al. studied the variations
Sense et al. discussed the quality of the electrodeposited films.
of the optical transmittance spectra of the ED-CISe films
The CISe film depended on the presence of pH buffer in the deposited on the plastic substrate, measured at room
bath.[175] The XRD patterns were measured for the as-deposited
temperature with a UV-Vis spectroscopy in transmission
samples from two types of baths. CISe films deposited from mode.[119] The optical transmittance spectra of as-deposited
non-pH buffered baths show pronounced (112) orientation, and annealed films with a step absorption edge at 1028 and
while films exhibiting more random orientation were obtained 1043 nm respectively.The energy gap from the intercept of the
from pH buffered paths. The patterns of both the samples showlinear portion of the curve on the horizontal axis is to be 1.195
weak and broad peaks characteristics of CISe chalcopyrite ± 0.005 eV and 1.180 ± 0.005 eV for the as-deposited and
phase, but with a high degree of amorphous or annealed CISe film respectively. The absorbance vs.
microcrystalline phase. One can note that when grown from a wavenumber is also estimated from FTIR (Fourier Transform
non pH buffered solution, the films appear to grow with some Infra-Red) spectroscopy in the near region (8500-15000 cm-1)
degree of (112) orientation when compared to the XRD pattern through the CISe film. From two traces, the straight-line
of the CISe film deposited from a pH buffered bath. Terasako behavior established the absorbance spectra of as-deposited
et al. studied the structural properties of CISe films, whichand annealed films with a step absorption edge at 9680 and
9470 cm-1, respectively. The bandgap energy estimated by this
were deposited by the SP technique.[2] For the XRD patterns of
the CISe films with different In/(Cu+In) ratios grown at Ts= spectrum was found to be 1.200 ± 0.005 and 1.174 ± 0.005 eV
360 ºC, all the films showed the 112 diffraction peaks. When for the as-deposited and the annealed film. The bandgap
the In/(Cu+In) ratio increases from 0.54 to 0.78, (112) XRD energy of this sample calculated from these two methods is
peak shifts continuously from 26.630 to 26.930. The weak almost equal. Furthermore, there is a change in the energy gap
XRD diffraction peaks (101), (211), (105)/ (213), (301), (417)/
between as-deposited and annealed films. This change might
(217) and (501) are unique to the chalcopyrite structure be due to the atom redistribution in CISe film. The value of
observed at the film with In/(Cu+In) ratio at 0.5. The XRD the absorption coefficient (α) depends on the preparative
diffraction peaks (301), (417)/ (217) and (501) peaks parameters of the respective methods. In the ED method, the
disappear for the ratio of 0.60. For more than 0.60 ratio, a the deposition potentialinfluenced the optical properties. The
diffraction peak due to In2Se3(110) can be observed. The described absorption coefficient for the sample prepared at
lattice constant was calculated from the 2θ values of (112) and
different potentials is a function of the photon energy.[133]
(312) diffraction peaks. The lattice constant a and c decreases Bindu et al. prepared CISe thin films through a new
with increasing the ratio. The lattice constant changes linearly
selenization process using CBD.[172] The optical band gap of
with increasing the In/(Cu+In) ratio. Therefore, the lattice prepared thin films decreased with an increase in Cu/In ratio.
constant along the axis obeys Vegard's law. Frontini et Cu rich films showed a high absorption coefficient. The
al.prepared CISe films on TiO2 substrates in citrate containing
absorption coefficient gets increases with Cu concentration
electrolytes by using techniques.[146] In this paper, CISe near the fundamental absorption edge. For Cu rich film, a
deposited on TCO/d-TiO2 and TiO2/nc-TiO2by ED at 6pH significant band tailing effect was observed in the absorption
value.A uniform deposition with compact surface and a multi- spectrum. From the transmission spectra of the CISe films,
nuclei cauliflower shape was observed.The stoichiometric Terasako et al. also discussed structural and optical properties
CISe sample was used as a good absorber material for highly of In-rich CISe polycrystalline films, which were prepared by
efficient solar cells.[176] Dharmadasa et al. investigated the
SP technique on a glass substrate in terms of In/(Cu + In)
stoichiometric change of the sample near the surface region ratio.[2] The optical plots of the films with various In/( Cu+In )
and confirmed the type of electronic conduction of the ratios grown at Ts = 360 and 400 oC were obtained. It can be
sample[121] Three separate samples were grown at cathodic seen that Eg shifts towards a higher energy side with an
voltages of a) 2.03, b) 2.46, and c) 2.70 V. The sample rich in
increasing In/(Cu+In) ratio. i.e. Eg value increased from 1.22
Cu at low cathodic voltages and rich in indium at high cathodic
to 1.36 eV as the In/( Cu+In) ratio increased from 0.67 to 0.78,
voltages.This quantitative analysis of sputter cleaned surfaces
while it was approximately 1.22 eV for the films with
also confirms the composition of the film changes as a 0.54<In/(Cu+In) < 0.67. Photoacoustic (PA) measurement was
function of the growth voltage. performed at room temperature under the modulation
frequency of 10 Hz. PA spectra of the films with various
3.2 Optical properties In/(Cu+In) ratios were observed. The arrow on each PA
Understanding and modeling of solar cell performance require spectrum indicates the Eg value determined by the optical
knowledge of the fundamental optical properties. The optical absorption measurements. For the film with (In/Cu+In) of 0.69,
properties of CISe are beneficial to study the electro- there is an absorption band with a peak energy of 0.8 eV. It can

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seem that the absorption band below the Eg becomes larger determined by metal to selenium ratio (Cu + In / Se).[179] If the
and broader with increasing the In/(Cu+In ) ratio. The main ratio was less than unity with excess Se, the film was p-type.
peak of the absorption band below Eg shifts towards a higher When the ratio was greater than unity with Se deficiency, it
energy side. For the film with In/(Cu+In) of 0.72, the PA signal was n-type, which can be made p-type by annealing. After
below Eg is extremely larger than above Eg owing to the annealing, the conductivity increases with increasing the Se
interband absorption. These results suggest that the content.[174] The resistivity of the prepared film depends on the
concentration of the point defects and impurities acting as the Cu:In ratio. The Cu rich solution shows the low resistivity as
non-radiative centers becomes larger with an increasing compared to the In-rich film. The resistivity of the films with
In/(Cu+In) ratio. Dharmadasa et al. discussed the variation a stoichiometric ratio of 1.5 was found to be a maximum 108
of the bandgap energy concerning the growth voltage for ohm.cm (intrinsic region). Shirakawa et al. studied the
electrodeposited CISe layers using a two-electrode system.[121] electrical properties of the CISefilms systematically in terms
From the optical absorption measurements of some of substrate temperature (Ts), pH, and Cu/In ratio[181]
selected sample, the continuous curve was drawn to indicate The variation of resistivity of the film also depends on the
the variation of the bandgap as the composition was changed substrate temperature. The films have been deposited from the
to include more indium in the layer. It was evident that the un-neutralized (pH = 1.9) and neutralized (pH = 4.0) spray
bandgap can be varied from ~1.00 to ~1.90 eV representing solutions with stoichiometric molar ratio (Cu/In=1.0). The
the two extreme values of ~ 1.00 ± 0.10 eV (bandgap of CISe) film resistivity increases with Ts for the un-neutralized
and ~ 1.90 eV (bandgap of InSe). At higher cathodic potential, solution (pH =1.9), while it decreases with Ts for the
the bandgap tends to decrease slowly, mainly due to the neutralized solution. The lower resistivity of the films for
inclusion of more indium in deposited layers. These results higher pH and higher Tsis considered to be mainly due to the
indicate that these layers can be used very effectively to larger hole mobility caused by the improved crystalline quality
fabricate multi-layers graded bandgap solar cell structures to of the film. The conductivity was found to be p-type. It
absorb a major part of the solar spectrum. Optical depends on the excess of Cu in the solution, which resulted in
spectroscopy was also employed to characterize the low resistivity films.[180]
nanocrystal. An increase in bandgap energy is one of the Some observation shows that the changes in the electrical
characteristics of the size quantization in semiconductor resistance are in agreement with composition, and phase
nanoparticle. The Bohr exciton radius of the CISe thin films evaluation. Saucedo et al.discussed the electrical properties of
was found to be 10.7 nm.[177] the CISe film deposited by the ED technique.[124] The average
resistance values of the three stages of the CISe film are
3.3 Electrical properties plotted as a function of the sample thickness.It is explained
The resistivity of the sample was calculated by two or four- that in a region I, the resistance increases up to 10 Ω for 250
probe method. In the case of CISe film, the graph nature of log nm thickness of the film, then it falls up to 2.3 Ω. This is not
ρ Vs. 1000/T shows that the resistivity decreases with an expected but the actual chemical reaction occurs at 250 nm,
increase in temperature. After annealing, the resistivity of which changes the phase and the electrical properties of the
CISe film decreases because it may be attributed to decreased complete film. Cu rich binary compound is responsible for the
defects or improvement in particle size.[178] This pattern gives electrical properties of the layer during the first nucleation
evidence of the semiconductor film. The variation of the stages. In the II-region, the resistance increases uniformly up
logarithm of conductivity with reciprocal of the temperature to 1 µm, thus indicating that the material added is more
was observed. The electrical conductivity of the sample at 308 resistant than the previous stage. This variation on the slope
K was found to be 1.4 x 10-18 (Ω cm )-1. The activation energy appears in this region due to the presence of ordered vacancy
of the CISe film was calculated by using the slope of the graph. compound. This measurement of the resistance measured is
The calculated activation energy was found to be 0.317 eV.[87] mainly related to this heavily disordered phase. However, in
Tomoakiet al. showed the activation energy lower than the region III, the material added should be more ordered and thus
bandgap energy.[160] This suggests the presence of localized more resistive, giving a higher slope. At this moment of
gap states below the conduction band edge. The activation growth, the addition of CuSe binary preferred, and the
energy for the chalcopyrite- phase formation (Ec) is larger than presence of different phases will control the resistance values
that for the sphalerite one (Es). To form the chalcopyrite and will be less dependent on the CISe presence. This is a
structures, additional energy is required to order the atoms direct indication of the importance of the secondary phases on
from the disordered sphalerite phase form. Therefore, the the electrical properties of CISe. However, after thermal
energy gained by the CISe films due to high temperature may treatment, the region II and III do not give significant change
enhance the production of the chalcopyrite-type film. CISe but in the region I, resistance decreases up to one order of
films can be either p-type or n-type depending on the Cu/ In magnitude. This change is due to the formation of the CuSe
ratio. from the original Cu2Se and Se resistivity. Valdes et al.
The electrical nature of the CISe film also depends on the studied the electric response of the cells, current-voltage
concentration of the Se in the precursor solution. It is curves of a representative device such as SnO2:F/TiO2 (100

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nm)/nc TiO2/In2Se3/CISe/graphite.[125] This combination that the cathode photocurrent increased in the direction of the
shows very good diode behavior with a rectification ratio cathode potential, i.e., it shows the CISe film with p-type
higher than 100 at ± 1 V. conductivity while the n-type conductivity of the sample. The
The complexing agent is used to reduce the activity of flat band potential (Vfb) of the p- and n-type conductivity was
copper ions and to shift the copper deposition potential in the found to be -0.85 and -0.82 V, respectively. Dharmadasa et al.
negative direction. It is also used to promote the formation of discussed the photo-electrochemical properties of the
more crystalline compounds. Frontini et al. studied the effect electrodepositedCISe layer.[121] In this case, the CISe film was
of the acidic electrolyte bath on the electrical properties of deposited by immersing the material layers in a suitable
CISe prepared by ED on dense and nanostructured TiO2.[146] In electrolyte, 0.01 M In2(SO4)3. The potential difference
the preparation of CISe film, citric acid was used as a between the sample and a graphite counterelectrodewas
complexing agent. In the presence of citrate, charge transfer measured under dark and white illumination conditions. The
reactions occur in several steps, lowering the deposition rate difference between the measured potential values provides the
and improving the overall quality of the film. It also PEC signal, which is the Voc of the junction under illumination.
contributes to buffering the solution pH. In this study, the The polarity of the PEC signal determines the electrical
electrochemical behavior of the CISe system was studied by conductivity type of the layer and the magnitude of the signal,
cyclic voltammetry on different substrates. The voltammetric indicating the suitability of the doping concentration of the
responses on TCO/d-TiO2 at pH 4 and 6 was obtained. In both semiconducting layer for fabricating electronic
+
solutions, two cathodic peaks were observed. Only a slight devices. The information that the p materials are deposited
[182]

difference in the position of the cathodic peak was observed (- at cathodic potential less than 2.20 V, P-type material
0.91 V at pH 6 and -1.10 V at pH 4). This difference is in good deposited at cathodic potential range 2.20 V to 2.34 V, intrinsic
agreement with that expected in response to the pH variation. material at 2.35 V, and n-type material at 2.36 to 2.80 V and n
The voltammetric response on TCO/d-TiO2/nc-TiO2 at pH 4 + materials above 2.80 V. Once these voltage values were

and 6 explains that the cathodic peak was observed (-1.29 V) established, any desirable semiconductor layer could be grown
at pH 4 and (-0.925V) at pH 6. The higher current densities are from this particular bath. Theoretically, the maximum value of
likely due to the nano-porous substrate. They concluded that - the Voc is calculated by dividing the bandgap energy by the
0.8 V is chosen as a suitable potential to produce the CISe film. charge of an electron (E0/e).[183]
The conversion efficiency of the solar cell is simply the
3.4 Photo-electrochemical Properties ratio of maximum power output to the incoming power. These
The thin-film solar cell is characterized by I-V measurements all electrical parameters are depending on the bandgap energy
in the dark and under illumination. The most important value of the absorber material. The Voc and FF of the solar cell
parameters of the solar cell are open circuit voltage (Voc), short are increased by increasing bandgap energy but Isc decreases
circuit current ( Isc), fill factor ( FF) and efficiency (η ), etc. correspondingly. The optimum band gap value for the
These parameters can be derived from the I-V curve, which is absorber material of a solar cell is about 1.5 eV which results
measured under illumination. Frontini et al. studied the in a theoretical maximum efficiency of 30%.[1] The efficiency
photo-response of the CISe film, which was deposited on the of the solar cell depends on the thickness of the absorber
TiO2 substrates with complexing agent citric acid.[146] The dark material (CISe) and the buffer layer (CdS). As the thickness
response indicates the diode behavior with good rectification. increases, the current density is improved. This is due to the
Anincrement in the current can also be seen when the sample increase in the photogenerated carriers in the absorber layer
is illuminated and for potential values higher than 0.5 V. Under consequent on the increase in optical absorption. An increase
radiation, the presence of the nanostructured TiO2 improves in the grain size with increasing the thickness was also
the performance of the cell. This is probably due to the bigger observed. There is a certain limit of thickness, after that
contact surface between the n- and p-type semiconductors. thickness, the efficiency is decreased.[184]
Smaller differences are found in the current increment for
CISe deposited on different substrates. The low energy 4. Post-deposition treatment
conversion in the illuminated I-V curve can also be associated CISe films were subjected to post-deposition treatments that
with fast electron-hole recombination in the TiO2/CISe included crystallinity improvement by annealing as well as
interface when the values of the Vocand Isc are minimum. The etching. The main purpose of treatment is to improve the
presence of a photocurrent proves the benefit of properties of the films to match better for photovoltaic
electrodepositing CISe using slightly acidic electrolytes on top purposes.
of a nano-crystalline substrate. Huang et al. further analyzed
the CISe sample, which was deposited on the flexible 4.1 Annealing
substrate.[119] Annealing of the CISe thin films can be deon at different
The photocurrent density versus the potential for annealed temperatures in various atmospheres such as vacuum, air,
CISe film was obtained under dark/illumination condition. argon, H2S, N2, etc. The main purpose of this treatment is to
The Cu/In ratio of the CISe film is 1.10 and 0.91. It is observed improve the film properties viz. crystal structure, surface

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morphology, grain size, etc. The deposited films contain many binary phases as Cu2Se segregated on the surface. The
impurities due to the precursor solutions and also contain some prevalent method for removing segregated Cu-Se and Cu-S
defects such as voids, pinholes, etc.[183] The annealing process phases is chemical etching in the KCN solution.[186] Another
decreases unwanted defects besides removing the impurities. approach to modify the surface is an exposure of the surface
It is an accepted fact that the properties of the films also to strong oxidants such as Br,[186] H2O2,[187] permanganates,[189]
depend on the crystal structure and grain size. or complexes.[190] Electrochemical oxidation is a useful surface
Heat treatment not only improved the crystallinity but also treatment technology. Although different research groups have
increased the grain size of the film material. Araujo et al. used electrochemical etching of CISe and CIS films for
synthesized CISe thin films on different substrates from the surface modification. Two different processing solutions and
alkaline medium by using ED.[122] The study was carried out at technologies were used for electrochemical etching: oxidation
pH 8.5 using di-ethylenediamine as a complexing agent for the in alkaline solution and electrochemical reduction-oxidation
Cu2+ ion. The as-deposited films were amorphous. Typical cycling in an acid solution. The influence of both
XRD patterns show the characteristic peaks (112), (220), (204), electrochemical etching on surface morphology and elemental
(312), and (116) for a CISe annealed film on Al, ITO glass and composition of thin films and on the electrical parameters of
steel. These peaks correspond to the chalcopyrite phase of the the complete solar cell are discussed in many pieces of kinds
CISe. Additionally, other observed diffraction peaksare are of literature Kois et al.grew the CISe film on the ITO surface
ascribed to In2O3, which could be formed during thermal by ED and annealed in a hydrogen atmosphere at 400˚C.[186] In
treatment. A considerable amount of In2O3 could be formed this literature, the microstructure of the film was studied using
during the annealing of the film deposited on Al and steel at cross-sectional SEM pictures. The CISe thin films with a
500C. This can occur by reacting with surface oxides of the thickness of about 0.8 μm were electrodeposited on an ITO
substrate. XRD pattern of CISe film on ITO shows a minor covered glass plate and annealed in a vacuum and showed a
amount of In2O3. So, ITO is a better option as compared to the dense, uniform structure. No grooves were detected on the
other substrate. Volobujeva et al. prepared CISe films by one surface.
step ED of CISe films, which were deposited on Mo-coated As a result of the removal of Cu2Se in the etching process
soda-lime glass substrate [185] of CISe films, the grain structure of the film was revealed. The
The effect of thermal treatment in a vacuum and under grain boundary cracks extending through the film were
selenium vapor pressure on the composition and structure of expanded. The chemical etching in KCN removes Cu2Se in
CISe has been investigated. Annealing in the atmosphere of Se addition to the surface from the inter grain area and leads to
vapor was provided in two-zone evacuated ampoules. The the formation of deep cracks through the film. At the cross-
pressure of selenium vapor was controlled by the temperature section of the electrochemically treated films, visible traces of
of the Se source zone and varied from 0.01 to 13 m bar. The corrosion occur. The films with large grains could be prepared
duration of the annealing was 30 min. At the end of annealing, by using the etching technique. It is also worth noting that the
the sample was pulled out and cooled down to room large grain films were easily optimized by chemical etching of
temperature. The duration of vacuum thermal treatments was the film with Cu rich compositions. Reports showed improved
in the range from 15 min to 12 h. The cross-section of the CISe efficiency of solar cells when etched CISe thin film was used
film was annealed under Se vapor pressure of 13 m bar and as an absorber layer. This etching process assumes importance
vacuum. The annealing temperature was 450C. The as- in absorber layer depositions. Before the preparation of
deposited films with thickness 1 μm are compact, uniform, and window layers, the Cu-Se layer is removed by the KCN
adherent. The formation of MoSe2 interlayer was observed in etching solution. The subsequent chemical etching of the layer
films thermally treated in selenium atmosphere as a result of in a KCN solution has shown to be successful in eliminating
diffusion of Se through CISe film and following reaction with the copper selenide phases, which were responsible for the
Mo back contact layer. However, the thickness MoSe2 layer remaining sub-bandgap absorption.[191]
grows with increasing the Se vapor pressure. At Se pressure KCN etching removes conductive copper selenide from the
0.01 m bar, it was 30 nm, at Se pressure about 13 m bar, the surface of Cu rich films but does not affect matrix composition.
thickness of the MoSe2 layer was 300 nm. The structure of The existence of a binary Cu-Se secondary phase aggregated
films annealed in a vacuum seems more uniform and nano- near the surface in the island regions of the film can be
crystalline (about 50 nm) as compared with all Se vapor determined by electron probe microanalysis (EPMA) before
pressure-treated films. etching the film in a 10 % KCN solution. It is proposed that
the Cu-Se phase present during the growth of Cu-rich CISe
4.2 Etching film enhances the mobility of atom on the substrate surface
The etching is the process of using strong acid to cut into the allowing the film to grow epitaxially to a critical thickness.
unprotected parts of a metal surface. This is a method of Bereznevet al. prepared CISe film by ED technique.[192] The
making a print from a metal plate that has been bitten with acid. XRD patterns of as-deposited, annealed, and etched CISe
CISe films prepared with an excess of Cu to promote the grain films were obtained. It can be seen that the as-deposited film
growth, need another processing step to remove separate is polycrystalline with diffraction peaks corresponding to

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either chalcopyrite or sphalerite phase. However, owing to the several compounds as stacked films that may react with each
poor crystallinity of the film, it is difficult to determine the other. High-efficiency solar cells based on CISehave all used
chalcopyrite phase. The formation of the chalcopyrite phase heterojunctions between a p-type (absorber) layer of CISeor a
was observed for the annealed film. The CISe preferred related alloy, and a transparent n-type CdS, ZnSe, ZnO, or
orientations (112), (220), and (116) for the film after annealing related compound layer. Substrates are generally glass, which
in vacuum were observed, which may be attributed to the is attractive for potential large-scale device applications
recrystallization and grain growth. because it is available at low cost in large areas with very
smooth surfaces. Solar cell preparation starts by the deposition
5. Application of CISe in solar cells of the p-type CISe absorber on the Mo-coated glass substrate,
In 1883, the first solar cell was built by Charles Fritts, who followed by the CdS or other weakly n-type buffer layer,
coated the semiconductor selenium with an extremely thin doped ZnO (transparent oxide), metal grids, and an anti-
layer of gold to form the junctions (1% efficiency). The reflecting coating. The obtained bulk conductivity of the CIS
demand for convenient energy such as electrical energy is thin-film is p-type and the surface conductivity is n-type.[143]
expected to grow in the future against the background of The key component of the solar cell configuration is the
global environmental problems. Solar energy needs to convert polycrystalline absorber film i.e. CISe.
into electrical energy, which is one of the most abundant, non- The performance of this material is strongly influenced by
pollutants, and inexhaustible source of energy. The main its grain size, grain orientation, loss mechanism originating
candidates for low-cost thin-film solar cell materials are from grain boundaries, and crystal defects. Regardless of the
amorphous hydrogenated silicon (a-Si:H), CdTe (cadmium deposition method, the absorber films of CISe based high-
telluride), and CISeand its alloys with Ga and/or S.[193-194] Of efficiency devices have smooth surface morphologies and
these, amorphous silicon solar cells currently have the largest consist of large density packed grains. The films are crystalline
market share.[195] The absorption coefficient of amorphous with a chalcopyrite structure, no additional phases are allowed
silicon is higher than that of crystalline silicon, which enables in the films. Copper selenide phases as well as indium selenide
its use in the thin-film form, and its bandgap is closer to the phases especially are detrimental to the solar cell
ideal value of about 1.5 eV. A serious disadvantage is the light- performance.[184] The Mo layer acts as the ohmic back contact
induced degradation of solar cells made of this material, which to the cell and also improves the adhesion between the glass
leads to a drop in conversion efficiency from the initial substrates and the active layers. The deposition of a thin (1µm)
value.[196] The polycrystalline compound semiconductor molybdenum layer onto the glass substrate by electron-beam
materials (CdTe and Cu(In,Ga)(S,Se)2) do not suffer from evaporation or sputtering is the first step in the fabrication
light-induced degradation. The performances of CIS-based process. The buffer layer also plays a very important role as a
solar cells have even shown some improvement after mechanical buffer. Since it protects the junction electronically
illumination under normal operating conditions. The prepared and mechanically against the damage that may otherwise be
samples were tested under two levels of irradiation. The induced by the oxide deposition. To improve the device
changes were observed in C-V characteristicsdemand long performance, a 50 nm thick CdS buffer layer is deposited
time degradation of CIGS solar cells.[197] Another advantage is between the absorber and window layers[183]
that they are direct bandgap materials with high absorption The thickness as well as the deposition method of the CdS
coefficients. The bandgap of CdTe (1.4 eV) is very close to the layer have a large impact on device performance. During the
ideal value. Despite that, the record efficiency for CdTe solar early days, the device structures consisted of a CISe/CdS
cells is only 16.5%, about half of the theoretical value.[198] Of junction with a thick (about 1–3 μm) CdS layer.[208-210] Garg
the candidate thin-film polycrystalline materials for solar cells, etal. reported the films were free from pinholes and cracks,
CISe and CdTe are the most promising with both close to the and found that they were suitable for solar cell applications
pilot production stage. The maximum reported efficiency after annealing.[208]
of’CISe-based cells is 14.1% for a small cell,[199] 11.2% The CdS layers of these devices were most often prepared
(aperture efficiency) for a 938-cm2-area device array [200], and by evaporation at substrate temperatures between RT and
10.4% (aperture efficiency) for a 3961-cm2-area panel.[201-202] about 200◦C, or in some cases by sputtering and the CdS film
CdTe has achieved 13.4% in small-area devices[203] and 7.3% was often doped with either In or Ga. For example, Stoltet al.
efficiency for a 929-cm2-area device array.[204] CISe-based reported the CuInSe cells with 14.8% efficiency with 513mV
solar cells have achieved efficiencies of over 14%. Only Voc, 71% FF and 40.4 mA/cm2 Jsc. In some cases, a CdS
recently, quantitative models of the device operation have bilayer was used,[210-211] consisting of a thinner high resistivity
been developed based on the model result,[205-207] it is likely that layer, prepared either by evaporation or chemical bath
improvements in Jsc and FF, can be achieved by improved deposition and a thicker low-resistivity layer, doped with 2%
device design. In or Ga. Evaporated CdS has been used also in combination
with the transparent conducting oxide layer [214-219]
5.1 Solid state solar cell (PV) Nowadays CBD is used almost exclusively. The CdS
The structure of this cell is quite complex since it contains buffer layer is lattice and electronically matched to the CISe

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Review article Engineered Science

absorber film and it presence controls the density of the on the prepared ITO/CISe/PANI/Ag photovoltaic structure. It
interface states and prevents the inter-diffusion species like Cu, was induced reversibly and repeatedly by the on-off cycles of
In, or Se etc. from the absorber into the ZnO window layer and IR irradiation. The results of C-V measurements (Mott-
vice versa. ZnO is the ideal window material due to its wide Schottky plot) at a frequency of 37 kHz for prepared structure.
bandgap (3.2 eV), higher temperature stability and the fact that The value of built-in potential Vbi = -2.15 eV was determined
it can be doped in any desired order. The rectifying junction by extrapolation to C-2= 0.M. Dharmadasa et al.developed a
was formed between absorber film p-type CISe film and n- low cost, large area multilayer graded bandgap solar cell
type ZnO window layer. The solar cell structure is completed structures, CISe layers were grown using simplified ED.
by used 1- 2 µm thick Al grid contact on to ZnO window layer. Dharmadasa etal. obtained bandgap variation together with
Absorption of light in the CdS layer, the bandgap of which is electrical conduction type changes, which are necessary to
2.4 eV, decreases the short circuit current density. The fabricate variation together with electrical conduction type
absorption of light in ZnO, in turn, is a less severe problem changes.[121] This experimental work enables the simultaneous
because its bandgap is higher, 3.2 eV. Therefore, a thinner CdS production of p-i-n type material layers together with bandgap
layer results in a better device performance due to reduced variation in the region of ~1.00 – 1.90 eV. XPS and XRF
absorption of light. Pillai et al. predicted the efficiency of the measurements confirm that it is possible to grow CISe layers
CISe/CdS solar cell.[184] The efficiency of this solar cell with p-i-n-type electrical conduction. XRF, XPS, and PEC
depends on the thickness of the CISe and CdS layer. measurement show that Cu-richness provides p-type
The CdS layer must be thick enough to obtain Vocand fill conduction and In richness provides n-type conduction in
factor. If the CdS layer is too thin or does not exist at all, electrodeposited CISe layers. In fabrication, glass/CG/n-CdS
recombination in the space-charge region of CISe increases, substrate as the cathode, and electrodeposited n-, i- and p-type
causing losses in Voc, FF, and spectral response. To reduce CISe layers as absorbers, four layers (n-n-i-p) graded solar cell
resistive losses, a 50 nm thick Ni layer can be included has been fabricated. After heat treatment at 350 ºC in a
between the ZnO window layer and Al grid contacts. selenium atmosphere, and etching in NaOH + Na2S2O3
Photovoltaic structures based on the electrically conductive solution, 2 mm diameter Au contacts were made for testing
polymer are currently intensively investigated to produce low these solar cell structures. These preliminary device structures
cost, large area, and flexible plastic photodiodes and solar show promising rectification properties. Under illumination
cells.[220-221] The configuration for all devices is based on the (AM 1.5), the devices are PV active producing typical values
mechanism of photo-induced electron transfer across the of Voc ~ 450 mV, Jsc ~ 20 mA cm2- and FF ~ 0.56. There are
internal or external donor-acceptor (D/A) heterojunction. different types of solid-state solar cells.
Notable examples include polymer/carbon,[222]
polymer/polymer,[223] polymer/organic,[224] and A) ETA solar cell
polymer/inorganic structures. Although a lot of electrically ETA stands for extremely thin absorber, and ETA solar cell is
conductive polymers were synthesized, polyaniline (PANI) an advanced photovoltaic design, where porous or structural
was one of the most intensively studied polymers during the material (2-10 µm in thickness) is coated with a layer of a
last decade. Bereznev et al. explained the electrochemical light-absorbing inorganic semiconductor. ETA solar cell
synthesis of In rich n-type CISe film with a thickness of about utilizing CuInX2 (X = S, Se, Te) technology is being developed
1 µm on to glass/ITO substrates was performed to achieve even greater efficiency and these have attracted
potentiostatically at the potential -900 mV vs SCE. The p-type attention because they required less space. One main feature
PANI layer was cast on to the glass/ITO/n-CISe substrate from of the ETA solar cell is the widely enlarged surface of the
PANI solution in chloroform. The thickness of the prepared substrate, e.g. porous TiO2, covered by a thin absorber layer.
PANI film was found at about 10 µm. Finally, the metal strip Due to this arrangement, the absorption is strongly enlarged.
(Ag) was evaporated on to the polymer layer. Electrical For this purpose, the absorber film must follow the internal
contacts were made on the ITO and metal with silver epoxy. porous surface.
The photovoltaic properties of structure under white light The ETA solar cell consists of an extremely thin-layer of-
illumination are superior from the tungsten halogen lamp with of CISe absorber material. It is sandwiched in between two
an intensity of 50 mW/cm2.The intensity of light produced a transparent semiconductors having a very high bandgap (3.73
Jscof 0.56 mA/cm2and a Vocof 31.3 mV. These photovoltaic eV), one semiconductor is p-type and another semiconductor
properties investigated that at the high thickness of CISe film, is n-type. Schematic ETA solar cells belong, as well as dye-
95 % of the incident light was absorbed and thus only 5 % of sensitized and organic solar cells, to composite solar cells
radiant power to reach the junction between the CISe and consisting of interpenetrating electron and hole conductors,
PANI layers. Therefore, thinner films could be used to between which an absorber is sandwiched. This allows using
improve the transmission of light. semiconductors with shallow diffusion length for the absorber.
The effective lifetime of photogenerated charge carriers 14 Since the absorber is thin in comparison to the absorption
µs was determined from the experimental curve. Photo- length of the bulk semiconductor, the internal surface area has
voltage change induced by switching the IR light on and off to be folded to increase the amount of material for absorption.

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Engineered Science Review article

ETA solar cells promise to be very cost-efficient since low- photoelectrode and counter electrode. This effect is called the
cost technologies can be applied. Applied materials are, for photo-electrochemical effect. The counter electrode is used as
example, TiO2 or ZnO as electron conductors, ternary material graphite and photoelectrode as CISe thin film. Using the
used as hole conductors.[133] polarity of the voltage developed in the PEC cell under the
illumination, one can find out the type of conductivity of the
B) Tandem solar cell material. The current-voltage characterization is used to find
This solar is merely two cells stacked one on top of the other. out junction identity factor (n), fill factor (ff), power
The advantage here is used two different bandgaps of two conversion efficiency (η) of the solar cell, etc. According to
semiconductors. The lower cell absorbs some of the light that the literature review, CISe based PEC solar cells were reported
passes through the upper cell. CISe is placed underneath GaAs. with a maximum efficiency of 9 %.[228] Danny et al. prepared
The tandem cell showed an AMO efficiency of 23 % more PEC cell configuration p-CISe/Polyiodide/C was formed. In
than the solid-state solar cell but twice the weight of the single that paper, anodic behavior occurs in the photo-voltage, it
GaAs cell.[224] The tandem cell represents a 2 to 3 present indicates the p-type nature of CISe. The I-V curve gives the
increase inefficiency. Where weight is not a major fill factor and efficiency, it was found to be 49.00 and 0.80 %
consideration, a tandem cell would be an excellent choice. respectively.[229] The value of Rs and Rush was found to be 5
Coutts et al. have analyzed the performance of tandem two and 10 kΩ respectively. Tembhurkar et al. prepared a PEC cell
junction cell and shown the optimum efficiency for the A.M. between spray pyrolytically deposited n-CISe/polysulphide n-
1.5 spectrum occurs with a top cell of 1.7 eV and a bottom cell CISe photoanode has been prepared by Spon to SnO2-
of 1.1 eV.[225] These band gaps are tightly constrained for two- deposited glass substrate, the effect of etching (HCl:HNO3 =
terminal cells, by the need to match photogenerated currents 5:1 by volume) on photoanode properties has been studied.[162]
in the top and bottom cell. Wuet al. have recently fabricated a The solar cell parameters are calculated. (Voc= 0.446 V, Jsc=
15 % four-terminal device based on CdTe and CISe.[226] It is a 18.32 ma/cm2, FF = 0.53 and η = 6.22 %.
multi-layered stack of thin films of different materials
deposited onto a substrate. The key features to observe here 6. Conclusion and future outlook
are: (1) there are two single-type or three-layer cells (each with An available literature survey on chemical methods reveals
a p-i-n configuration) stacked on top of one another; (2) these that it indeed offers an attractive method to prepare CISethin-
two single cells are physically inseparable from each other (as film materials for solar cells. The quality and properties of the
deposited in this device configuration). These two points are thin films largely depend on the preparative parameters of the
key to understanding how a tandem cell works, and why respective methods. The properties of the CISe thin films are
measurements performed on them are necessarily different easily tailored by adjusting or optimizing the preparative
from those done on a single device. Under white light parameters, which in turn are suitable for a solar cell
illumination, then this would require the bottom i-layer to be application. From a practical point of view, the relative metal
much thicker and/or have a narrower energy bandgap than the concentrations in solution must be adjusted empirically to
top i-layer to have the same amount of optical absorption. obtain a desired ratio of the metal in the film.
Nanu et al. fabricated a nanocomposite 3 D solar cell by using This review focuses on some low-cost methods, which are
technique.[227] This study focused on the low-cost preparation useful to prepare good CISe thin film. To lower the production
of thin-film TiO2/CuInS2 nanocomposite solar cells. However, costs of photovoltaic modules, alternative, low-cost deposition
we can manufacture 3 D solar cells based on the CISe thin film. methods need to be developed. There is probable room for
The active p-n heterojunction is folded and fills in the space different deposition processes for different applications, that
between the contacts. Light absorption and charge separation is, higher cost methods may be used in high-value applications
take place inside the nanocomposite. Cheap deposition like in satellites, where high efficiency is crucial. Whereas less
techniques such as SP and industrial-grade chemicals of only expensive methods may be needed to achieve low prices for
95 % purity can now be used to obtain photovoltaic (PV) solar mass products. The latter may become more critical when
cells. Literature reveals the low-cost preparation of thin-film photovoltaic become more and more conventional means of
TiO2/CuInS2 nanocomposite 3 D solar cells. However, due to energy production.
poor quality of the obtained absorber, the conversion Technology in the present century requires the
efficiency was very low, typically 1-2 %. To improve miniaturization of the devices into nanometer size with the
efficiency, CISe is a good choice for absorber material in 3-D dramatically enhanced ultimate performance. This raises
solar cells. We can improve the quality of the thin film with issues regarding new materials for achieving functionality and
considerable efficiency of 3-D solar cells. selectivity. Low-cost methods should be selected to give a
good quality thin films. Chemical methods are the right choice
5.2 Liquid state solar cell (PEC) for these objectives. These methods are useful to make
This solar cell mainly consists of a photo-electrode, electrolyte, nanostructure material, nano-phase, or nanostructured
and C-counter electrode. When the photoelectrode is materials research. However, the nanocrystalline natures of
illuminated by light, then a voltage is developed across the the CISe thin films open the new window in the energies field

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Review article Engineered Science

of nanoscience technology. Indeed, the development of CISe Film, 2004, 133, 451-452, doi: 10.1016/j.tsf.2003.11.003.
thin films will help to improve solar cell efficiency and further [5] A.V. Postnikov, M.V. Yakushev, Thin Solid Film, 2004, 141,
research will produce innovation that will benefit industries 451, doi: 10.1016/j.tsf.2003.11.005.
and society. [6] A. Brummer, V. Honkimaki, P. Berwin, V. Probst, J. Palm, R.
Hock, Thin Solid Film, 2003, 437, 297, doi: 10.1016/S0040-
Acknowledgments
6090(03)00685-0.
The authors are thankful to the Indian Space Research
Organization-Savitribai Phule Pune University, Pune Science, [7] M.A. Contreras, M.J. Romero, B. To, F. Hasoon, R. Noufi, S.
and Technology Cell (ISRO-SPPU STC) for partial financial Ward, K. Ramanathan, Thin Solid Film, 2002, 204, 403
assistant. doi:10.1016/S0040-6090(01)01538-3.
[8] L. L. Kazmerski, M. S. Ayyagari, F. R. White, G. A. Sanborn,
Supporting Information J. Vac. Sci. Technol., 1976, 13, 139, doi: 10.1116/1.568808
Not applicable [9] K. W. Mitchell, C. Eberspacher, J. Omar, D. Pier, Proc. 20th
IEEE Conf. Photovolt. Specialists, Las Vegas, 1988, 1384.
Conflict of interest [10] J. E. Jaffe, A. Zunger, Phys. Rev. B, 1984, 29, 1882, doi:
There are no conflicts to declare. 10.1103/PhysRevB. 29.1882.
[11] K. W. Mitchell, Proc. 4th Int. Photovolt. Sol. Eng. Conf.,
List of symbols and abbrevations
1989, 889.
Symbol Abbreviation [12] L. L. Kazmerski, S. Wagner, ‘Current Topics in
CISe Copper Indium Di-selenide Photovoltaics, 1985, 1, 67.
Voc Open Circuit Voltage [13] Fatima Zohra Satour, Ameur Zegadi, Infra. Phy. and Tech.,
PVD Physical Vapor Deposition 2019, 96, 238–243, doi: 10.1016/j.infrared.2018.11.035
CBD Chemical bath deposition [14] Ali Murat Soydan, Pinar Yilmaz, and Bahadur Tunaboylu,
CED Chemical Electro-deposition 2018, 7, doi:10.1155/2018/5187960.
SILAR Successive Ionic Layer and adsorption reaction
[15] H. S. Min, S. Mandati, R. Chandran, A. Mallik, M. Arif, S.
Bhuiyan and K.G. Deepa, Orient. J. Chem., 2019, 35, 01-13.
SP Spray Pyrolysis
[16] M. Kemell, M. Rital, and M. Leskel, Solid State and Mater.
F:SnO2 Fluorine doped Tin Oxide
Sci., 2005, 30, 1–31, doi: 10.1080/10408430590918341.
OVC Ordered vacancy compound [17] T. Feurer, R. Carron, G. T. Sevilla, F. Fu, S. Pisoni, Y.E.
ITO Indium doped tin oxide Romanyuk, S. Buecheler, and A. N. Tiwari, Adv. Energy Mater.
M-CBD Modified chemical bath deposition 2019, 9, 1901428, doi: 10.1002/aenm.201901428.
[18] R. R. Pottier, J. R. Sites, IEEE Trans. Elect. Devices., 1984,
Isc Short Circuit Current
31,571, doi:10.1109/T-ED.1984.21571.
FF Fill Factor
[19] T. Irie, S. Endo, S. Kimura, Jpn.J. Appl. Phys.,1979, 18, 1303,
Η Efficiency
doi: 10.1143/JJAP.18.1303.
Jsc Short current density
[20] J. C. Garg, R.P. Sharma, K.C. Sharma, Thin Solid Film, 1988,
ETA Extremely Thin Absorber
164, 269, doi: 10.1016/0040-6090(88)90148-4
Pmax Maximum Power [21] K. D. Becker, S. Wagner, Phys. Rev., (B), 1983, 27, 5240, doi:
RT Room temperature 10.1103/PhysRevB.27.5240.
XRD X Ray diffraction [22] H. G. Bruhl, H. Neumann, T. Pfieffer, G. Kuhn, Phys. Status
Α Absorption Coefficient Solid(a), 1981, 66, 597.
[23] P. W. Li, R.A. Anderson, R. H. Plovnick, J. Phys. Chem.
References: Solids., 1979, 40, 333, doi: 10.1016/0022-3697(79)90113-6.
[1] H. M Pathan, C. D Lokhande. Bull. Mater. Sci., 2004, 27, 2, [24] L. Stephanie, G. Sheila, P. Ryne, Kulbinder, K.F. Chem.
doi: 10.1007/BF02708491. Mater.,2003, 15, 3142-3147, doi: 10.1021/cm034161o.
[2] T. Terasako, U. Yuji, K. Tetsuya, S. Shirakat. Sol. Ene. Mate. [25] J. E. Jaffe, A. Zunger; Phy. Rev. B, 1983, 28, 10,
& Sol. Cells, 2006, 90, 262–275, doi: 10.1002/pssc.200669597
doi:10.1103/PhysRevB.28.5822.
[3] J. Muller, J. Nowoczin, H. Schmitt, Thin Solid Film, 2006,
496, 364, doi: 10.1016/j.tsf.2005.09.077. [26] J. Zank, M. Mehlin, and H. P. Fritz, Thin Solid Film, 1996,
[4] M.V. Yakushev, A. V. Mudryi, V. F. Gremenok, E. P. 286, 259, doi: 10.1016/S0040-6090(95)08214-X.
Zaretskaya, V. B. Zalesski, Y. Feofanov, R.W. Martin, Thin Solid [27] C. Guillen, M. A. Martınez, and J. Herrero, Vacuum, 2000,
58, 594, doi: 10.1016/S0042-207X(00)00355-9.

© Engineered Science Publisher LLC Eng. Sci., 2020, 12, 52-78 | 71

Engineered Science Review article

[28] T. L. Chu, S. S. Chu, S. C. Lin, and J. Yue, J. Electrochem. [49] H.-W. Schock and R. Noufi, Prog. Photovolt.: Res. Appl.,
Soc., 1984, 131, 2182, doi:10.1149/1.2116044. 2000, 8,151, doi: 10.1002/(SICI)1099-
[29] A. Garg, K. S. Balakrisnan, and A. C. Rastogi, J. 159X(200001/02)8:1<151::AID-PIP302>3.0.CO;2-Q.
Electrochem.Soc., 1994, 141, 1566, doi: 10.1149/1.2054963. [50] S. Siebentritt, Thin Solid Film, 2002, 1, 403–404, doi:
[30] A. C. Rastogi, K. S. Balakrisnan, R. K. Sharma, and K. Jain, 10.1016/S0040-6090(01)01525-5
Thin Solid Film, 1999, 357 179, doi: 10.1016/S0040- [51] ASTM E927-91. Standard specification for solar simulation
6090(99)00649-5. for terrestrial photovoltaic testing.
[31] C. Guillen, and J. Herrero, Thin Solid Film, 1998, 323, 93, [52] ASTM G159-98. Standard tables for references solar spectral
doi: 10.1016/S0040-6090(97)01038-9 irradiance at air mass 1.5: Direct normal and hemispherical for
[32] M. E. Calixto, and P. J. Sebastian, J. Mater. Sci,1998, 33, 339, a37 tilted surface (E891 & E892).
doi: 10.1023/A:1004311527795. [53] D. M. Chapin, C. S. Fuller, and G. L. Pearson, J. Appl. Phys.,
[33] G. Hodes, T. Engelhardt, D. Cahen, L. L. Kazmerski, and C. 1954, 25, 676, doi: 10.1063/1.1721711.
R. Herrington, Thin Solid Film, 1985, 128, 93, doi: [54] M. A. Green, K. Emery, D. L. King, S. Igari, and W. Warta,
10.1016/0040-6090(85)90338-4. Prog. Photovolt: Res. Appl., 2003, 11, 347, doi: 10.1002/pip.499.
[34] S. R. Kumar, R. B. Gore, and R. K. Pandey, Thin Solid Film, [55] V. M. Fthenakis, S. C. Morris, P. D. Moskowitz, and D. L.
1993, 223, 109, doi: 10.1016/0040-6090(93)90733-6. Morgan, Prog. Photovolt.: Res. Appl., 1999, 7, 489, doi:
[35] H. P. Fritz and P. Chatziagorastou, Thin Solid Film, 1994, 10.1002/(SICI)1099-159X(199911/12)7:6<489::AID-
247, 129, doi: 10.1016/0040-6090(94)90485-5. PIP287>3.0.CO;2-N.
[36] V. K. Kapur, B. M. Ba¸sol, and E. S. Tseng, Sol. Cells, 1987, [56] T. Wada, N. Kohara, S. Nishiwaki, and T. Negami, Thin Solid
21, 65, doi:10.1016/0379-6787(87)90105-0. Film, 2001, 387, 118, doi: 10.1016/S0040-6090(00)01846-0.
[37] P. P. Prosini, M. L. Addonizio, A. Antonia and S. Loreti, Thin [57] D. Schmid, M. Ruckh, and H.W. Schock, Sol. Energy Mater.
Solid Film, 1996, 288, 90, doi: 10.1016/S0040-6090(96)08817-7. Sol. Cells, 1996, 41-42, 281, doi: 10.1016/0927-0248(95)00107-
[38] M. Altosaar, E. Mellikov, J. Kois, Y. Guo, and D. Meissner, 7.
Proceedings of Joint International Meeting of The [58] H. W. Schock and U. Rau, Physica B, 2001, 1081, 308–310,
Electrochemical Society, Inc. and The International Society of doi: 10.1016/S0921-4526(01)00863-8.
ElectrochemistryParis, France, 1997, 1314. [59] T. F. Ciszek, J. Cryst. Growth, 1984, 70, 405, doi:
[39] C. D. Lokhande, Mater. Chem. phy., 2005, 28, 145-149. doi: 10.1016/0022-0248(84)90294-X.
10.1016/j.matchemphys.2005.03.051. [60] J. H. Ermer and R. B. Love, European patent application,
[40] R.W. Birkmire and E. Eser, Annu. Rev. Mater. Sci., 1997, July 10, 1986.
27, 625, doi: 10.1146/annurev.matsci.27.1.625. [61] A. Rockett, T. C. Lommasson, L. C. Yang, H. Talieh, P.
[41] A. Goetzberger, J. Luther, and G. Willeke, Sol. Energy Mater. Campos, and J. A. Thornton, J. Appl. Phys., 1991, 70, 1505.
Sol. Cells, 2002, 74,1, doi: 10.1016/S0927-0248(02)00042-9 [62] I Mart and J. Santamaria, E. Iborra, G. Gonzalez-Diaz, and
[42] R. W. Birkmire, Sol. Energy Mater. Sol. Cells, 2001, 65, 17, F. Sanchez- Quesada, J. Appl. Phys., 1987, 62, 4163, doi:
doi: 10.1016/S0927-0248(00)00073-8. 10.1063/1.339135.
[43] A. Goetzberger and C. Hebling, Sol. Energy Mater. Sol. [63] F. Sanchez-Quesada, C. Case, G. Gonzalez-Diaz, R.
Cells,2000, 62, 1, doi: 10.1016/S0927-0248(99)00131-2 Beaulieu, and J. J. son, A. E. Hill, and D. G. Armour, Jpn. J. Appl.
[44] A. Shah, P. Torres, R. Tscharner, N. Wyrsch, and H. Keppner, Phys, 1980, 19, 15, doi: 10.7567/JJAPS.19S3.15.
Science, 1999, 285, 692, doi: 10.1126/science.285.5428.692. [64] N. A. K. Abdul-Hussein, A. N. Y. Samaan, R. D. Tomlinson,
[45] J. F. Guillemoles, L. Kronik, D. Cahen, U. Rau, A. Jasenek, Cryst. Res. Technol. 1985, 20, 509.
and H.-W. Schock, J. Phys. Chem. B,2000, 104, 4849, doi: [65] G. Dagoury, D. Vigner, and R. Lesueur, Proceedings of the
10.1021/jp993143k. 9th Inter-national Vacuum Congress and Sth International
[46] U. Rau and H.W. Schock, Appl. Phys. A: Mater. Sci. Process, Conference on SolidSurfaces, Sept. 26, 1, 1983, edited by J. L.
1999, 69, 131, doi: 10.1007/s003390050984. Segovia, ASEVA, Madrid, Spain, 1983, 128
[47] A. Rockett and R. W. Birkmire, Appl. Phys., 1991, 70, R81, [66] A. N. Y. Samaan, N. Abdul-Karim, N. Abdul-Hussein, R. D.
doi: 10.1063/1.349175. Tomlin-son, A. E. Hill, and D. G. Armour, Jpn. J. Appl. Phys.,
[48] B. J. Stanbery, Rev. Solid State Mater. Sci., 2002, 27, 73, doi: 1980, 19, 15, doi: 10.7567/JJAPS.19S3.15.
10.1080/20014091104215. [67] J. A. Thornton, Sol. Cells, 1987, 21, 41, doi: 10.1016/0379-
6787(87)90103-7.

72 | Eng. Sci., 2020, 12, 52-78 © Engineered Science Publisher LLC

Review article Engineered Science

[68] J. A. Thornton, T. C. Lommasson, H. Talieh, and B.-H. T [86] P. P. Hankare, K. C. Rathod, P. A. Chate, A.V. Jadhav, I.S.
seng, Sol. Cells, 1988, 24,1, doi: 10.1016/0379-6787(88)90030- Mulla, J. Alloy and Comp., 2010, 78, doi:
0. 10.1016/j.jallcom.2010.03.215.
[69] J. Santamaria, I. Martil, E. Iborra, G. Gonzalez-Diaz, and F. [87] R.H. Bhari, L. A. Patil, P.S. Sonawane, M.D. Mahanubhav,
Sanchez-Quesada, Sol. Cells, 1990, 28, 31, doi: 10.1016/0379- V. R. Patil, P. K. Khanna, Mater. Letts., 2007, 61, 2058–2061, doi:
6787(90)90036-5. 10.1016/j.matlet.2006.08.015.
[70] B. Schumann, A. Tempel, and G. Kuhn, Sol. Cells, 1986, 16, [88] S. M. Chauhan, S. H. Chaki, M.P. Deshpande, Jiten P. Tailor,
43, doi: 10.1016/0379-6787(86)90074-8. A. J. Khimani Maters. Sci. Semicon. Proce., 2018, 74, 329–335,
[71] N. Takenoshita, Sol. Cells, 1986, 16, 65, doi: 10.1016/0379- doi: 10.1016/j.mssp.2017.11.008.
6787(86)90075-X [89] R.N. Bhattacharya, A.M. Fernandez, M.A. Contreraz, J.
[72] F. J. Pern, J. Goral, R. J. Matson, T. A. Gessert, and R. Noufi, Keane, K. Tennant, K. Ramanathan, J. R. Tuttle, R.N. Noufi, A.
Sol. Cells,1988, 24, 81, doi: 10.1016/0379-6787(88)90038-5. M. Hermann, J. Electrochem. Soc., 1996, 43, 854, doi:
[73] X. Qui and I. Shih, Can. J. Phys.,1987, 65, 1011, doi: 10.1016/0038-1101(96)00045-7.
10.1139/p87-163 [90] R. N. Bhattacharya, J.F. Hiltner, W. Batchelor, M.A.
[74] Y. Ueno, H. Kawai, T. Sugiura, and H. Minoura, Thin Solid Contreras, R.N. Noufi, J.R. Sites, Thin Solid Film, 2000, 361,
Films, 1988, 157, 159, doi: 10.1016/0040-6090(88)90356-2 396-399, doi: 10.1016/S0040-6090(99)00809-3
[75] D. Pan, X. Zhang, G. Yang, Y. Shang, F. Su, Q. Hu, R. R. [91] S. Jost, F. Hergert, R. Hock, J. Schulze, A. Kirbs, M. Vob, M.
Patil, H, Liu, C. Liu and Z. Guo, Ind. Eng. Chem. Res., 2020, 59, Purwins, M. Schmid, Sol. Energy Mater. Sol. Cells, 2007, 91, 636,
20371-20381, doi: 10.1021/acs.iecr.0c04510. doi: 10.1016/j.solmat.2006.12.012.
[76] G. Hades and D. Cahen, Sol. Cells, 1986, 16, 245, doi: [92] Y. Ueno, H. Kawai, Sugiura, H. Minoura, Thin Solid Film,
10.1016/0379-6787(86)90088-8. 1988, 157, 159-168, doi: 10.1016/0040-6090(88)90356-2.
[77] F. J. Garcia and M. S. Tomar, Jpn. J. Appl. Phys.,1983, 22, [93] L. Thouin, S. Massaccesi, S. Sanchez, and J. Vedel, J.
535, doi: 10.7567/JJAPS.22S1.535. Electroanal. Chem., 1994, 374, 81, doi: 10.1016/0022-
[78] N. Arita, N. Suyama, Y. Kita, S. Kitamura, T. Hibino, N. 0728(94)03352-8.
Takada, K. Omura, N. Ueno, and M. Murozono, Proceedings of [94] T. Pottier and G. Maurin, J. Appl. Electrochem. 1989, 19, 361,
the 20th Institute of Electrical and Electronics Engineers doi: 10.1007/BF01015237.
Photovoltaic Specialists Conference, Las Vegas, September 26- [95] A. N. Molin, A. I. Dikusar, G. A. Kiosse, P. A. Petrenko, A.
30, 1988 (Institute of Electrical and ElectronicsEngineers, New I.Sokolovsky, and Yu. G. Saltanovsky, Thin Solid Film, 1994, 237,
York, (1988). 1650. 66, doi: 10.1016/0040-6090(94)90239-9
[79] T L. Chu, S. S. Chu, S. C. Lin, and J. Yue, J. Electrochem. [96] A. N. Molin and A. I. Dikusar, Thin Solid Films, 1994, 237,
Sot., 1984, 131, 2182, doi: 10.1149/1.2116044 72, doi: 10.1016/0040-6090(94)90240-2.
[80] G. Hades, T. Engelhard, D. Cahen, L. L. Kazmerski, and C. [97] M. G. Ganchev and K. D. Kochev, Sol. Energy Mater. Sol.
R. Herrington, Thin Solid Films, 1985, 128, 93, doi: Cells, 1993, 31, 163, doi: 10.1016/0927-0248(93)90048-8
10.1016/0040-6090(85)90338-4. [98] C. Guillen, and J. Herrero, J. Electrochem. Soc., 1994, 141,
[81] V. K. Kapur, B. M. Basal, and E. S; Tseng, in Proceedings of 225, doi: 10.1149/1.2054688.
the 7thInternational Conference on Ternary and Multinary [99] Y. Ueno, H. Kawai, T. Sugiura, and H. Minoura, Thin Solid
Compounds, edited by S. K. Deb and A. Zunger (Materials Films, 1988, 157, (1988) 159, doi: 10.1016/0040-
Research Society, Pittsburgh,1986, 219. 6090(88)90356-2.
[82] D. Lincot, M. Froment, and H. Cachet, in Advances in [100] R. P. Raffaelle, H. Forsell, T. Potdevin, R. Friedfeld, J. G.
ElectrochemicalScience and Engineering, Vol. 6, R. C. Alkire, D. Mantovani, S. G. Bailey, S. M. Hubbard, E. M. Gordon, and A.F.
M. Kolb, Eds., Wiley-VCH, Weinheim, Germany, (1999) 165. Hepp, Sol. Energy Mater. Sol. Cells,1999, 57, 167, doi:
[83] R. N. Bhattacharya, J. Electrochem.Soc. 1983, 130, 2040, 10.1016/S0927-0248(98)00180-9.
[101] E. Tzvetkova, N. Stratieva, M. Ganchev, I. Tomov, K.
doi: 10.1149/1.2119516.
Ivanova, and K. Kochev, Thin Solid Films, 1997, 311, 101,
[84] J. C. Garg, R. P. Sharma, and K. C. Sharma, Thin Solid doi:10.1016/S0040-6090(97)00263-0.
Films, 1988, 164, 269, doi: 1016/0040-6090(88)90148-4. [102] T. Edamura, and J. Muto, J. Mater. Sci. 1994, 5, 275, doi:
[85] R. N. Bhattacharya, W. Batchelor, J. E. Granata, F. Hasoon, 10.1007/BF00921251.
H. Wiesner, K. Ramanathan, J. Keane, and R. N. Noufi, Sol. [103] A. Kampmann, V. Sittinger, J. Rechid, and R. Reineke-
Energy Mater. Sol. Cells, 1998, 55, 83, doi: 10.1016/S0927- Koch, Thin Solid Films, 2000, 361, 309, doi: 10.1016/S0040-
0248(98)00049-X. 6090(99)00863-9.
© Engineered Science Publisher LLC Eng. Sci., 2020, 12, 52-78 | 73
Engineered Science Review article

[104] N. B. Chaure, J. Young, A. P. Samantilleke, and I. M. [123] K. T. L. De Silva, W. A. A. Priyantha, J.K.D.S. Jayanetti,
Dharmadasa, Sol. Energy Mater. Sol. Cells, 2004, 81, 125, doi: B.D. Chithrani, W. Siripala, K. Blake, I.M. Dharmadasa, Thin
10.1016/j.solmat.2003.10.001. Solid Film, 2001, 382, 158-163, doi: 10.1016/S0040-
[105] R. N. Bhattacharya, J. F. Hiltner, W. Batchelor, M. A. 6090(00)01185-8.
Contreras, R. N. Noufi, and J. R. Sites, Thin Solid Films, 2000, [124] E. Saucedo, C.M. Ruiz, E. Chasseing, J.S. Jaime-Ferrer, P.P.
361, 396, doi: 10.1016/S0040-6090(99)00809-3. Grand, G. Savidand, V. Bermudez, Thin Solid Film, 2010, 518,
[106] R. N. Bhattacharya, W. Batchelor, K. Ramanathan, M. A. 3674-3679, doi: 10.1016/j.tsf.2009.09.113.
Contreras, and T. Moriarty, Sol. Energy Mater. Sol. Cells, 2000, [125] M. Valdes, M. Vazquez, A. Goossens, Electrochimica Acta,
63, 367, doi: 10.1016/S0927-0248(00)00056-8. 2008, 54, 524-529, doi: 10.1016/j.electacta.2008.07.036.
[107] P. Garg, A. Garg, A. C. Rastogi, and J. C. Garg, J. Phys. D: [126] Y. Sudo, S. Endo, Irie, T., Appl. Phys., 1993, 32, 1562-1567,
Appl.Phys.,1991, 24, 2026, doi: 10.1088/0022-3727/24/11/018 doi: 10.1143/JJAP.32.1562.
[108] S. N. Sahu, R.D. L. Kristensen, and D. Haneman, Sol. [127] N. Khare, G. Razzini, L.P. Bicelli, Thin Solid Film, 1990,
Energy Mater., 1986, 18, 385, doi: 10.1016/0165- 186, 113-128, doi: 10.1016/0040-6090(90)90505-8.
1633(89)90063-4. [128] C.P. Chien, S.B. Fine, T.L. Chu, S.S. Chu, Polycrystalline
[109] Y. Sudo, S. Endo, and T Irie, Jpn. J. Appl. Phys.,1993, 32, Thin Film Review Meeting, SERI, Golden, Co, 1984, 43.
1562, doi: 10.1143/JJAP.32.1562. [129] J.L. Xu, X.F. Yao, J.Y. Feng, The influence of the vacuum
[110] M. C. F. Oliveira, M. Azevedo, and A. Cunha, Thin Solid annealing process on electrodeposited CuInSe 2 film, Sol. Energy
Films, 2002, 405, 129, doi: 10.1016/S0040-6090(01)01720-5. Mater. Sol. Cells, 73(2002) 203-208
[111] M. E. Calixto and P. J. Sebastian, Sol. Energy Mater. Sol. [130] R.N. Bhattacharya, Solution growth and electrodeposited
Cells, 2000, 63, 335, doi: 10.1016/S0927-0248(00)00053-2. CuInSe2 thin films J electrochem. Soc., 1983, 130, 2040, doi:
[112] R. Ugarte, R. Schrebler, R. C´ordova, E. A. Dalchiele, and 10.1149/1.2119516.
H. Gomez, Thin Solid Films, 1999, 340, 117, doi: 10.1016/S0040- [131] T. Pottier, G. Maurin, J. Appl. Electrochem., 1989, 19, 361-
6090(98)01361-3. 367, doi: 10.1007/BF01015237.
[113] C. D. Lokhande, J. Electrochem. Soc. 1987, 134, 1727, [132] J. S. Wellings, N.B. Chaure, S.N. Heavens, I.M.
10.1149/1.2100745, doi: 10.1149/1.2100745. Dharmadasa, Thin Solid Film, 2008, 516, 3893-3898, doi:
[114] S. Nomura, K. Nishiyama, K. Tanaka, M. Sakakibara, M. 10.1016/j.tsf.2007.07.156.
Ohtsubo, N. Furutani, and S. Endo, Jpn. J. Appl. Phys., 1998, 37, [133] C. Guillen, J. Herrero, Sol. Energy Mater. Sol. Cells, 1996,
3232, doi: 10.1143/JJAP.37.3232. 43, 47-57, doi: 10.1016/0927-0248(95)00163-8.
[115] S. N. Qiu, L. Li, C. X. Qiu, I. Shih, and C. H. Champness, [134] P. Garg, A. Garg, A.C. Rastogi, J.C. Garg, J. Phys. D: Appl.
Sol. Energy Mater. Sol. Cells, 1995, 37, 389, doi: 10.1016/0927- Phys., 1991, 24, 2026-2031, doi: 10.1088/0022-3727/24/11/018
0248(95)00033-X. [135] A. Ashour, A. A. Ramdhan, K. Abd El-Hady, A.A. Akl, J.
[116] M. Pourbaix, Atlas of Electrochemical Equilibria in Mater.Sci.: Mater. Electron, 2008, 16, 599, doi: 10.1007/s10854-
Aqueous Solutions, Pergamon Press, New York, 1966. 005-3233-0.
[117] M. Kemell, Academic dissertation, 2003 [136] S.N. Sahu, R.D.L Kristensen, D. Haneman, Sol. Energy
[118] S. Beyhan, S. Suzer, F. Kardirgan, Sol. Energy Mater. Sol. Mater., 1989, 18, 385-397, doi: 10.1016/0165-1633(89)90063-
Cells, 2007, 91, 1922-1926, doi: 10.1016/j.solmat.2007.06.017. 4.
[119] C. J. Huang, T. H. Meen, M. Y. Lai, W. R. Chen, Sol. Energy [137] R. Pal, K. K. Chattopadhyay, S. Chaudhari, A. K. Pal,Sol.
Mater. Sol. Cells, 2004, 82, 553-565, doi: Energy Mater. Sol. Cells, 33, 241, doi :10.1016/0927-
10.1016/j.solmat.2003.12.008. 0248(94)90210-0.
[120] J.S. Welling, A. P. Samantilleke, S.N. Heavens, P. Warren, [138] M.E. Calixto, P. J. Sebastian, Sol. Energy Mater. Sol. Cells,
I.M. Dharmadasa, Sol. Energy Mater. Sol. Cells, 2009,93, 1518- 2000, 70, 335-345, doi: 10.1016/S0927-0248(00)00053-2.
1523, doi: 10.1016/j.solmat.2009.03.031. [139] P.J. Sebastian, M.E. Calixto, R.N. Bhattacharya, R. Noufi,
[121] I. M. Dharmadasa, R. P. Burton, M. Simmonds, Sol. Sol. Energy Mater. Sol. Cells, 1999, 59, 125-135, doi:
Energy Mater. Sol. Cells, 2006, 90, 2191-2200, doi: 10.1016/S0927-0248(99)00037-9.
10.1016/j.solmat.2006.02.028. [140] S. Bereznev, J. Kois, I. Golovtsov, A. Opik, E. Mellikov
[122] J. Araujo, R. Ortíz, A. López-Rivera, J.M. Ortega, M. Thin solid films, 2006, 511, (2006) 425-429, doi:
Montilla, D. Alarcón, J Solid State Electrochem, 2007, 11, 407– 10.1016/j.tsf.2005.11.074.
412, doi: 10.1007/s10008-006-0162-7.

74 | Eng. Sci., 2020, 12, 52-78 © Engineered Science Publisher LLC

Review article Engineered Science

[141] M. Benaicha, N. Benouattas; V. Benazzouz; Ouahab L. Sol. [163] R.A. Michelson, W. S. Chen; in proceeding of the 16th
Energy Mater. Sol. Cells, 2009, 93, 262-266, doi: IEEE on specialist Conference, San Diago, 1982,781.
10.1016/j.solmat.2008.10.014. [164] Jang Bo Shim, Chang Gyoun Kim, Dong Ju Jeon, Taek-Mo
[142] T. Whang, V. Hsieh; Y. Kao; S. Lee, Appl.Sur. Sci., 2009, Chung, Ki-Seok An, Sun Suk Lee, Jong Sun Lim, Seok Jong
255, 4600-4605, doi: 10.1016/j.apsusc.2008.11.081 Jeong, Bo Keun Park, Young Kuk Lee, J.l of Phy.and Chem. of
[143] E. Tzvetkova, M. Ganchev; I. Tomov; K. Kochev, Thin Solids, 2013, 74, 867–871, doi: 10.1016/j.jpcs.2013.02.002.
Solid Films, 1997, 311, 101-106. [165] S. Sugan, K. Baskar, R. Dhanasekaran, Curr. Appl. Phys.,
[144] A.N. Molin, A.I. Dikusar, G.A. Kiosse, P.A. Petrenko, A.I. 2014, 14, 1416e1420, doi: 10.1016/j.cap.2014.08.011.
Sokolovsky, Yu.G. Saltanovsky, Thin Solid Films, 1994, 237, 66- [166] Kegao Liu, Hui Liu, Yong Xu, Li Zhang J.Appl. Biomater.
71, doi: 10.1016/0040-6090(94)90239-9. Funct. Mater., 2016, 14, S77-S79, doi: 10.5301/jabfm.5000305
[145] J. Yang, Z. Jin, C. Li, W. Wang, Y. Chai, Electrochem. [167] J. Ramkumar, S. Ananthakumar, S. Moorthy Babu Solar
Commun., 2009,11, 711-714, doi: 10.1016/j.elecom.2008.12.062 Energy, 2014, 106, 177-183, doi: 10.1016/j.solener.2014.04.010.
[146] M.A. Frontini, M. Vazquez, J Mater Sci, 2010, 45, 2995- [168] Jeng-Shin Ma, Subrata Das, Che-Yuan Yang, Fuh-Shan
3000, doi: 10.1007/s10853-010-4300-3. Chen, Chung-Hsin Lu, Ceram. Internat., 2014, 40, 7555–7560,
[147] S. Bereznev, J. Kois, E. Mellikov, A. Opik, Materials and doi: 10.1016/j.ceramint.2013.12.106
technologies for photovoltaic applications from Estonia, Baltic [169] A. A. Akl, H.H. Afify, Mater. Resear. Bulle.,2008, 43, 1539-
polymer Symposium, 2001,148-154. 1548, doi: 10.1016/j.materresbull.2007.06.018.
[148] M.C.F. Oliveira, M. Azevedo, A. Cunha, Thin Solid Films, [170] A. Zouaoui, M. Lachab, M. L. Hidalgo, A. Chaffa, C.
2002, 405, 129-134, doi: 10.1016/S0040-6090(01)01720-5. Llinares, N. Kesri, Thin Solid Films,1999, 339, 10, doi;
[149] M.I. Alonso, K. Wakita, J. Pascual, M. Garriaga, A. 10.1016/S0040-6090(98)00893-1.
Yamamoto, Cond-mat, 2001, 14, 0112048, doi: [171] J. R. Tuttle, D. S. Albin, R. Noufi, Solar Cells, 1991, 30, 21,
10.1103/PhysRevB.63.075203. doi: 10.1016/0379-6787(91)90034-M.
[150] H. M. Pathan, J.D. Desai, C. D. Lokhande, Appl. Surf. Sci., [172] K. Bindu, C. Sudha kartha, K. Vijayakumar; T. Abe, Y.
2002, 202 47-56, doi: 10.1016/S0169-4332(02)00843-7. Kashiwaba, Sol. Energy Mater. Sol. Cells,2003, 79, 67-79, doi:
[151] J. Yang, Z. Jin, Y. Chai, H. Du, T. Liu, T. Wang, Thin Solid 10.1016/S0927-0248(02)00367-7.
Film, 2009, 517, 6617-6622, doi: 10.1016/j.tsf.2009.04.050. [173] J. Yang, Z. Jin, C. Li, W. Wang, Y. Chai, Electrochem.
[152] H.M. Pathan, C.D. Lokhande, App. Surf. Sci., 2005, 245, Commun., 2009, 11, 711-714, doi: 10.1016/j.elecom.2008.12.062.
328-334, doi: 10.1016/j.apsusc.200410.025 [174] T. Yamaguchi, M. Naka, S. Nllyama, T. Imanishi, J.Phys.
[153] T. Yukawa, K. Kuwabara, K. Koumoto, Thin solid films, Chem. Solids, 2005, 66, 2000, doi: 10.1016/j.jpcs.2005.09.073.
1996, 286, 151-153, doi: 10.1016/S0040-6090(96)08545-8. [175] C. Sene, M. Calixto; K. Dobson, R. Birkmire, Thin Solid
[154] M. B. Dergacheva, V. V. Chaikin, Russ. J. Appl. Chem., Films, 2008, 516, 2188-2194, doi: 10.1016/j.tsf.2007.07.142
2008, 81, 614, doi: 10.1134/S1070427208040083. [176] M. Kemell, M. Ritala, M. Leskela, Crit. Rev. Solid State, 30
[155] N. Kavear, M. Hyland; R. Hill, Turk. J. Phys. 1993, 17, 818. (2005) 1, doi: 10.1080/10408430590918341.
[156] Yu. V. Rud, Semiconductors, 1999, 33, 870, doi: [177] W. E. Devaney, R.A. Michelson, W. S. Chen, Proc. 18th
10.1134/1.1187801. IEEE Conf. Photovolt. Specialists., New York, 1985, 1733.
[157] J. Yang, Z. Jin, Y. Chai, H. Du, T. Liu, Mater.letters, 2008, [178] C. H. Fischer, H. J. Muffler M. Bar T. Kropp, A.
62, 4177-4180, doi: 10.1016/j.matlet.2008.05.065. Schonmann S. Fiechter, G. Barbar, M. C. Lux-Steiner, J. Phys.
[158] R.S. Patil, C.D. Lokhande, R.S. Mane, H.M. Pathan, J. Oh- Chem. B, 2003, 107, 7516-7521, doi: 10.1021/jp034911h
Shim; H. Sung-Hwan, Sci. and Engg. B, 2006, 129, 59-63, doi: [179] D. Pertain, Solar cells and their application, Wiley, 1995,
10.1016/j.mseb.2005.12.027. 600.
[159] P. S. Patil, Mater. Chemistry and Physics, 1999, 59, 185- [180] G. Hodes, G. Alexandrowitz, D. Cahen, Tech. Rep. Nov.
198, doi: 10.1016/S0254-0584(99)00049-8. 1984 to Feb. 1985., Proj. No. IL-5-041-32-1 to SERI (USA)
[160] T. Tomoaki, S. Inoue; T. Kariya, S. Shirakata, Sol. Energy [181] S. Shirakata, M. Tomonori, K. Tetsuya, I. Shigehiro, Jpn J.
M a t e r. S o l . C e l l s , 2 0 0 7 , 9 1 , 1 1 5 2 - 1 1 5 9 , d o i : Appl. Phys., 1996, 35, 191-199, doi: 10.1143/JJAP.35.191.
10.1016/j.solmat.2006.06.063. [182] S. Dennison, J. Mater. Chem.,1994,4,41, doi:
[161] S. Shirakata, M. Tomonori, K. Tetsuya, I. Shigehiro, Jpn J. 10.1039/JM9940400041
Appl. Phys., 1996, 35, 191-199, doi: 10.1143/JJAP.35.191. [183] P. Kistiah, M. Satyanarayana, Journal of material science
[162] Y. D. Tembhurkar, J.P. Hirde, Thin solid films, 1992, 215, Letters, 1984, 3, 767-772, doi: /10.1007/BF00727968.
65-70, doi: 10.1016/0040-6090(92)90702-D.

© Engineered Science Publisher LLC Eng. Sci., 2020, 12, 52-78 | 75

Engineered Science Review article

[184] V. Pillai, K. P. Vijayakumar, Sol. Energy Mater. Sol. Cells, [203] T. L. Chu, performance measured at the Solar Energy
1984, 51, 47-54, doi: 10.1016/S0927-0248(97)00207-9. Research Institute.
[185] O. Volobujeva, J. Kois, K. Traksmaa, K. Muska V. [204] S. P. Albright, J. F. Jordan, B. Ackerman, and R. R.
Bereznev, M. Grossberg, E. Mellikov, Thin solid films, 2008, 516, Chamberlin, Sol.Cells, 1989, 27, 77, doi; 10.1016/0379-
7105-7109, doi: 10.1016/j.tsf.2007.12.024. 6787(89)90018-5.
[186] J. Kois S. Bereznev O. Volobujeva, E. Mellikov, Thin solid [205] K. W. Mitchell and H. I. Liu, Proceedings of the 20th
films, 2007, 515, 5871-5875, doi: 10.1016/j.tsf.2006.12.157 Institute of Electrical and Electronics Engineers Photovoltaic
[187] B. Canava, J. F. Guillemoles, J. Vigneron D. Lincot A. Specialists Conference, Las Vegas, September 26-30, 1988
Etcheberry, J. phys. Chem. Solids,2003, 64,1791, doi: (Institute of Electrical and Electronics Engineen, New York, 1988,
10.1016/S0022-3697(03)00201-4. 1461.
[188] K. Muller, R. Scheer, Y. Burkov, D. Schemeiber, Thin solid [206] M. Roy, S. Damaskinos, and J. E. Phillips, Proceedings of
films, 2004, 451, 120, doi: 10.1016/j.tsf.2003.11.001. the 20th Institute of Electrical and Electronics Engineers
[189] S. Percharmant, J. F. Guillemoles, J. Vedel, D. Lincot, Photovohaic SpeciaiistsConference, Las Vegas, September 26-30,
11th Int. Conf. on Ternary and Multinary Compounds ICTMC-11 1988, Institute of Electrical and Electronics Engineers, New York,
Salford, 1997, 719. 1988, 1618.
[190] T. Delsol, M. C. Simmonds, I. M. Dharmadasa, Sol. Energy [207] M. Roy, Ph.D. dissertation, University of Delaware, 1988.
Mater. Sol. Cells, 2003, 77, 331, doi: 10.1016/S0927- [208] P. Garg, A. Garg, A. C. Rastogi, and J. C. Garg, J. Phys. D:
0248(02)00352-5. Appl. Phys. 1991, 24, 2026, doi 10.1088/0022-3727/24/11/018.
[191] M.E. Calixto, P.J. Sebastian, Sol. Energy Mater. Sol. Cells, [209] S. N. Sahu, R.D. L. Kristensen, and D. Haneman, Sol.
2000, 70, 335-345, doi: 10.1016/S0927-0248(00)00053-2. Energy Mater., 1989, 18, 385, doi: 10.1016/0165-
[192] S. Bereznev, J. Kois, E. Mellikov, A. Opik, Baltic polymer 1633(89)90063-4.
Symposium, 2001,148-154. [210] C. X. Qiu, and I. Shih, Can. J. Phys. 1987, 65, 1011, doi:
[193] A. Goetzberger, J. Luther, and G. Willeke, Sol. Energy 10.1139/p87-163.
Mater. Sol. Cells,2002,74,1. [211] L. Stolt, J. Hedstr¨om, J. Kessler, M. Ruckh, K.-O. Velthaus,
[194] R. W. Birkmire, Sol. Energy Mater. Sol. Cells, 2001, 65, 17, and H.-W. Schock, Appl. Phys. Lett., 1993, 62, 597, doi:
doi: 10.1016/S0927-0248(00)00073-8. 10.1063/1.108867.
[195] A. S. Bahaj, Energy, 2002, 27, 97, doi: 10.1016/S0960- [212] V. K. Kapur, B. M. Ba¸Sol, and E. S. Tseng, Solar cells, Sol.
1481(01)00162-8. Cells, 1987, 21, 65, doi: 10.1016/0379-6787(87)90105-0.
[196] A. Shah, P. Torres, R. Tscharner, N. Wyrsch, and H. [213] S. N. Qiu, L. Li, C. X. Qiu, I. Shih, and C. H. Champness,
Keppner, Science, 1996, 285, 692, doi: Sol. Energy Mater. Sol. Cells, 1995, 37, 389, doi: 10.1016/0927-
10.1126/science.285.5428.692. 0248(95)00033-X.
[197] T. Kojima, T. Koyanagi, K. Nakamura, T. Yanagisawa, K. [214] J. Hedstr¨om, H. Ohlsen, M. Bodegard, A. Kylner, L. Stolt,
Takahisa, M. Nishitani, and T. Wada, Sol. Energy Mater.Sol. Cells, D. Hariskos, M. Ruckh, and H.-W. Schock, Conf. Rec. 23rd IEEE
1998, 50, 87, doi: 10.1016/S0927-0248(97)00126-8. Photovolt. Spec. Conf. IEEE, Piscataway, N.J., 364, 1993.
[198] M. A. Green, K. Emery, D. L. King, S. Igari, and W. Warta, [215] A. Rockett and R. W. Birkmire, J. Appl. Phys., 1991, 70,
Prog.Photovolt. Res. Appl., 2003, 11, 347, doi: 10.1002/pip.499 R81, doi: 10.1063/1.349175.
[199] K. W. Mitchell, C. Eberspacher, J. Ermer, K. Pauls, D. Pier, [216] D. Schmid, M. Ruckh, F. Grunwald, and H. W. Schock, J.
and D. Tanner, Proceedings of the Photovoltaic Science and Appl. Phys., 1993 73, 2902, doi: 10.1063/1.353020.
Engineering Conference, Sydney, Australia, February, 1989, 14- [217] Y. Sudo, S. Endo, and T. Jpn. J. Appl. Phys.,1993, 32, 1562,
17. doi: 10.1143/JJAP.32.1562.
[200] K. W. Mitchell, C. Eberspacher, J. H. Ermer, K. L. Pauls, [218] R.W. Birkmire and E. Eser, Annu. Rev. Mater. Sci.1997, 27,
and D. N. CuInSe2 cells and modules, Pier, IEEE Trans. Electron 625, doi: 10.1146/annurev.matsci.27.1.625.
Devices, 1990, 37, 410. [219] H.-W. Schock and R. Noufi, Res. Appl. 2000, 8,151, doi:
[201] D. E. Carlson, The Physics of Hydrogenated Amorphous 10.1002/(SICI)1099159X(200001/02)8:1<151::AID-
Silicon I, Structure, Preparation, and Devices, edited by D. PIP302>3.0.CO;2-Q.
Joannopoulos and J. Lucovsky, Springer, Berlin, 1984, 203-241. [220] C. J. Brabec, N. S. Sariciftci, J. C. Hummelen, Adv. Funct.
[202] C. Eberspacher, J. Ermer, C. Frederic, C. Jensen, R. Gay, D. Mater., 2001, 11, 1-15, doi: 1002/1616-
Pier, D. Willett, and F. Farg, in Proceedings of the 10th EC 3028(200102)11:1<15::AID-ADFM15>3.0.CO;2-A.
Photovoltaic Solar Energy Conference, 1991.

76 | Eng. Sci., 2020, 12, 52-78 © Engineered Science Publisher LLC

Review article Engineered Science

[221] G. Yu, A. J. Heeger, J. Appl. physics., 1995, 78, 4510, doi: Maharashtra State in 2009, and Best Teacher Award from
10.1063/1.359792. Shivaji University in 2010. He is presently an editorial board
[222] J. J. M. Halls, R. H. Friend, Synth. Met., 1997, 85, 1307, member of “Electrochemical Energy Technology,” De
doi: 10.1016/S0379-6779(97)80252-4.
Gruyter; the fellow, Maharashtra Academy of Sciences from
2012; an expert member, distinguished visiting professor in
[223] P. J. Sebastian, S. A. Gamboa, M. E. Calixto, H. Nguyen-
polymer chemistry, Institute of Chemical Technology, Mumbai
Cong, P. Chartuer, R. Perez, Semicond. Sci. Echnol.,1998, 13, from 2012. He is the author of more than 600 papers in
1459, doi: 10.1088/0268-1242/13/12/023. international journals with “h” index 90 and more than
[224] C.D. Lokhande, J. Electrochem. Soc., 1987, 134, 1727, doi: 29,000 citations, edited 11 books, filed more than 45 patents,
10.1149/1.2100745. and directed more than 60 Ph.D. theses. Recently, he has
[225] T. J. Coutts, K.A. Emery, S. Ward, Prog. Photovolt. Res. been listed at first position in top 2% scientists in the subject
Appl., 2002, 10, 195, doi: 10.1002/pip.491. of Applied Physics in India by the Stanford University Survey
[226] X. Wu, J. Zhou, A. Duda, J.C. Keane, T.A. Gessert, Y. Yan,
R. Nou, Mater. Res. Symp. Proc., 2005, 865, F11.4.1.
Dr. H. M. Pathan received his
Ph.D. in 2003 from Shivaji
[227] J. Piekoszewski; J. J Loferski.; R. Beaulieu; J. Beall; R.
University, Kolhapur, India.
Roessler; J. Shewchun, Sol. Energy Mater., 1980, 2, 363, doi: Afterwards, he joined with Prof.
10.1016/0165-1633(80)90012-X. O. S. Joo at the Korea Institute of
[228] R. Durny, A. E. Hill, R. D. Tomlinson, Thin Solid Films., Science and Technology Seoul,
1980, 69, L11, doi: 10.1016/0040-6090(80)90044-9 South Korea, as a post-doctoral
[229] J. Burdick, T. Glatfelter, Solar Cells, 1986, 18,301-314, fellow in 2004. Since 2008 he is
doi: 10.1016/0379-6787(86)90129-8. full Assistant professor in Physics
at the department of Physics Savitribai Phule Pune University
Maharashtra, India and Visiting Professor Chonbuk National
Author information
University, Iksan, Republic of Korea, 1-15 May, 2018. His
research is focused on material science, energy conversion
Prof C D Lokhande is presently and storage devices, solar cell and supercapacitors. He is also
working as a Dean and Research the Coordinator of the UPE-II for DSSC group. Chief Guest
Director at D Y Patil Education Editor: J. Nanotechnology Special issue Functional
Society (Deemed to be University), Nanomaterials. Guest Editor: J Mater Sci Mater Elect Special
Kolhapur, India.He has been issue: Mater. Photovoltaics from Solar Asia 2015. He is Life
working on several areas of thin Member/Member of different institutions/organizations and is
film technology, ranging from lead Guest Editor for Special issues etc. He is the author of
chemical synthesis of thin films to more than 100 articles in peer-reviewed international journals
their applications in solar cells, and 5 review articles with 2800 citations and the founding
gas sensors, and supercapacitors. Executive Editorial board of ES Energy & Environment
Moreover, he made a great contribution in designing several journal.
prototype devices such as supercapacitors and
heterojunction-based room temperature gas sensors. He Dr. Balasaheb M. Palve Palve
received his Ph.D. from Shivaji University, Kolhapur in 1984, is presently working as an
without viva voce examination as his thesis was adjudged as assistant professor at the
“Excellent.” Later, in 1987, he joined as assistant professor Department of Physics, S.N. Arts,
in Physics and became professor and Head at Shivaji D.J. M. Commerce, B.N.S.
University, Kolhapur, immediately after accomplishing his Science College, Sangamner. He
first postdoctoral stay at the Weizmann Institute of Science, received his Ph.D. from the
Israel. He has won many awards and received many honors. Department of Physics,
He was appointed as Fellow of Institute of Physics, London, Savitribai, Phule Pune
in 1990; was visiting scientist in the Indo-Polish CEP scheme University, India under the
in 1991; was INSA Visiting Fellow in 1993; is the first guidance of Dr. H.M. Pathan in 2018. He completed his M.Sc
recipient from Shivaji University of the prestigious Alexander in Material Science from the Department of Physics,
von Humboldt Fellowship, Germany, in 1996 and Brain Pool Savitribai Phule Pune University, India in 2008. He has been
fellowship of South Korea in 2003; was participant in Noble working on thin-film technology and its application in various
Laureates Meeting, Lindau, Germany in 2001; was visiting types of solar cells. He has published 15 research papers in
professor at Hanyang University, South Korea in 2006; was an international and national reputed journal. He is presently
awarded a RajyaShishakPurshakar, Government of working as a reviewer of various journals such as
© Engineered Science Publisher LLC Eng. Sci., 2020, 12, 52-78 | 77
Engineered Science Review article

Electrochimica Acta, Journal of Material Science, Material Mr. Vishal Sunil Kadam is
Science in semiconductor processing, Material research presently completing his Ph.D. at
express, etc. He has participated in various International and the Department of Physics,
National conferences based on material science. He was Savitribai Phule Pune University,
awarded the Inspiration teacher award from S.N. Arts, D.J.M. Pune under the guidance of Dr. H.
Commerce, B.N.S. Science College Sangamner, India in 2018. M. Pathan. His research is
focused on the third generation
Miss Chaitali Vishwas Jagtap solar cell. He has more than 20
is presently working as Women publications in International
Scientist under the WOS-A journals. 5 years of research
scheme of the Department of experience on nanomaterials synthesis and characterization
Science and Technology, for Sensor and solar cell application from Advanced Physics
Government of India at Laboratory, Department of Physics, Savitribai Phule Pune
Advanced Physics Laboratory, University, Pune, and Center for Material for Electronics
Department of Physics, Technology (C-MET), Pune. He has worked on various
Savitribai Phule Pune fabrication of metal oxide photoanodes by spray pyrolysis,
University, Pune under the chemical bath deposition, SILAR.
guidance of Dr. H. M. Pathan. She has more than 15
publications in International journals. She received her M.Sc. Publisher’s Note: Engineered Science Publisher remains
degree in 2014 from Fergusson College, Pune, and M.Phil. neutral with regard to jurisdictional claims in published maps
degree in 2018 from Savitribai Phule Pune University. Her and institutional affiliations.
work is focused on Dye Sensitized Solar Cell. She has worked
on various synthesis and fabrication of various metal oxides
semiconductors such as TiO2, ZnO, etc.

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