Supervised By:
Dr. Shaista Shehzada
Presented By:
Wasifa
Zulfiqar:1121-FBAS/MSCPHY/F20
Namra Altaf:1127-FBAS/MSCPHY/F20
Ambreen
Bashir:1128-FBAS/MSCPHY/F20
Project Title
Study of Ga doped ZnO nanostructures
through Laser Ablation
Outline
Introduction
Introduction of Zinc Oxide
Applications of Zinc Oxide
Introduction of Gallium
Application o Gallium
Laser Ablation
Experimental Setup
Characterization Techniques
X-ray Diffraction
Photoluminescence
UV-Vis Spectroscopy
Results and Discussion
Conclusion
INTRODUCTION
What is nanotechnology?
What are nano-particle?
Properties of Nano-particles
Size
High surface or volume ratio
Introduction of Zinc Oxide
• Zinc oxide is a white colored inorganic compound that is insoluble
in water.
• It is naturally found as a mineral zincite.
• It has a direct band gap (3.3eV) at room temperature.
• It can absorb UV-visible light.
Structure:
ZnO
Structure of
ZnO
Introduction of Gallium
• Gallium is a blue-grey metal with a orthorhombic structure.
• Atomic number is 31.
• Gallium is a soft, silvery metal in standard temperature and pressure.
• Belongs to group 13 of periodic table.
• It has high boiling point 2204ºC.
Gallium
Applications of Gallium
• Mobile Phones
• LED’s (Blue and Green)
• Alloys
• Pressure sensors for touch switches
• Radar
• Space
Laser Ablation
• Laser Ablation or Photoablation is the process of removing material from a solid
surface by irradiating it with a laser beam.
Working:
• It produces nanoparticles by using a powerful laser beam that hits
the target material.
• During this process, the precursor (source material) vaporizes due
to the high energy of the laser irradiation and it results in
nanoparticle formation.
Experimental
Parameters
Sample Wavelengt Energy Time Repetiti Pulse Pulse
No. h mJ min on rate width duration
nm Hz ns ns
Sample 1 1064 40 30 10 5 6
Ga-ZnO
40
Sample 2 1064 50 30 10 5 6
Ga-ZnO
50
Characterization Techniques
X-Ray Diffraction
Photo Luminescence
UV-Visible Spectroscopy
X-Ray Diffraction: (XRD)
• (XRD) is a technique used in materials science to determine the
crystallographic structure of a material.
• Find average spacing between layers or rows of atoms.
• Used to find crystallite size and shape.
• Crystal structure of an unknown substance .
• The crystallite size of nanoparticles is calculated by Debye Scherrer formula
• which is given as
• D=(kλ/β cos θ)
XRD Graphs
2θ θ COS θ FWHM D Davg
Ga-
40 mJ 30.12 15.06 0.965 0.051 28.05 24.67
2
32.29 16.14 0.960 22.55 -
0.064
0
36.87 18.43 0.948 0.062 23.42 -
4
Fig.1 XRD spectrum of Ga-ZnO 40
XRD Graph
Table
2θ θ COSθ FWHM D Davg
32.27 16.13 0.690 0.062 23.13 28.63
4
35.02 17.51 0.953 0.046 31.07 -
8
36.83 18.41 0.948 0.046 31.23 -
8
48.14 24.07 0.913 0.046 32.43 -
8
57.20 28.51 0.878 0.062 25.29 -
Sample 2 4
Photo Luminescence:
• Photoluminescence is the emission of light
which is caused by the irradiation of material
with other light.
• In Photoluminescence, light is directed onto a
sample where it is absorbed and where a
process called photo-excitation can occur.
• Photoluminescence spectroscopy is a widely
used technique for characterization of the
optical and electronic properties such as
excitation and defects.
Photo
Luminescence
PhotoLuminescence (PL)
Sample Maximum Band Gap
No. peak (eV)
position
(nm)
Sample 1 488 nm 2.59 eV
Ga-40
Sample 2 482 nm 2.57 eV
Ga-50
UV-Visible Spectroscopy:
• UV-Visible spectroscopy is the
attenuation of a beam of light
passing through a sample or after
reflection from sample surface.
• Spectroscopy is the study of
interaction between light and
matter.
UV-Visible
Spectroscopy
UV-Visible Spectroscopy
Fig.5 UV-Vis Absorbance Fig.6 UV-Vis spectrum of Ga-ZnO 40
spectrum of Ga-ZnO 40
UV-Visible Spectroscopy
Fig.7 UV-Vis Absorbance spectrum of Fig.8 UV-Vis spectrum of Ga-
Ga-ZnO 50 ZnO 50
Conclusion
s:
XRD data showed the
UV Visible spectroscopy.
PL measure
