Analyze the structural and spectroscopic properties of nanostructured GaN: ZnO Solid solution. For this, we used techniques like X-Ray Diffraction (XRD) for phase identification and analyzing the crystalline structure of the material, Diffuse Reflectance Spectroscopy (DRS) for measuring the characteristic reflectance spectrum which contains information about the optical properties and structure of the sample being measured. The characterizations conducted showed the incorporation of Ga and N ions in ZnO framework and a resulting modification in bandgap.

1. Study on structural and
spectroscopic properties of
nanostructured GaN:ZnO
Solid solution

2. NANOTECHNOLOGY
* Study and application of extremely small things at
Nano scale (about 1-100 nm).
* Nanotechnology helps us to see and control atoms and
molecules individually.
* First discussed by Richard Feynman in his talk ‘There’s
Plenty of Room at the Bottom ‘in the year 1959 and the
term “Nano-technology” was first used by Norio
Taniguchi in the year 1974.

3. NANOMATERIAL
* Materials with external/internal/surface structure in nanoscale.
* Have enhanced properties such as higher strength, light weight, increased
control of light spectrum and greater chemical reactivity.
* Nanomaterial is synthesized using ‘Bottom-up approach’ and ‘Top-down
approach’.
Fig.1 (A) Piezoelectric actuators (B) Water splitting

4. PHOTOCATALYSIS
* Photocatalyst is a material that absorbs light for chemical
transformation of reactants and remains unaltered at end of
the reaction.
* Combination of two Greek words “photo”-light and
“catalysis” -acceleration of chemical reaction by a catalyst.
* Photocatalysis was discovered by Honda and Fujishima in
1972.

5. X-RAY DIFFRACTION (XRD)
SPECTROSCOPY
* Techniques used for :
-Characterization of crystalline materials.
-Determination of unit cell dimensions.
-Measurement of sample purity.
* The interplanar spacing can be calculated by employing
Bragg’s equation:
d=
nλ
Sinθ
* Crystallite size can be calculated using Scherrer equation:
D =
Kλ
βCosθ
(K-shape factor(0.9 ))
* Micro-strain can be calculated using the formula:
ε =
βcosθ
4 sinθ
=
β
4tanθ
Fig.2 Schematic Diagram of X-ray
Diffractometer
Fig.3 X-ray Diffractometer

6. * Lattice parameters are calculated using equation:
1
d²
=
4
3
(h2+hk+k2)
a²
+
l²
c²
* Bond length can be calculated using formula:
l =
𝑎2
3
+
1
2
− 𝑢
2
∗ 𝑐² (positional parameter, u =
𝑎²
3𝑐²
+ 0.25)
* Volume of the unit cell can be calculated using relation:
V = 0.866*a2*c
Fig.4 X-ray powder diffractogram

7. RESULTS AND DISCUSSION
XRD ANALYSIS:
 Ga conc. increases,(101) peak
shifts to higher 2θ value.
 Variation in lattice parameters,
strain and particle size of the
samples with increasing Ga conc.
has been calculated and
tabulated.
 As Ga conc. increases, strain
increases and particle size
decreases.
 Samples A,B & C mentioned are
Ga & N co-doped ZnO with Zn/Ga
molar ratio 10%(C),15%(B) &
20%(A) respectively.
Fig.5 XRD graph of Ga doped ZnO
Ga
Conc.
%mol
D
(nm)
d
(Å)
a
(Å)
b
(Å)
c
(Å)
Strai
n
ε
×10-3
Bond
Length
(Å)
Vol.
(Å)3
10% 34.49 2.15 3.25 3.25 5.20 2.88 1.588 47.56
15% 31.32 2.15 3.25 3.25 5.20 3.18 1.589 47.69
20% 29.07 2.15 3.25 3.25 5.20 3.43 1.588 47.58
Table 1

8. Fig.6 Williamson-Hall plot

9. DIFFUSE REFLECTANCE SPECTROSCOPY (DRS)
* Measures the characteristic reflectance spectrum produced
when light is passed through a medium.
* This spectrum contains the optical properties and structure of
the sample.
* Theory used to describe and analyze diffuse reflectance spectra
is the Kubelka-Munk theory.
* The Kubelka-Munk function F(R∞);
F(R∞) =
(1−R∞)²
2R∞
=
K
S
Fig.7 UV-Visible-NIR Spectrophotometer.

10. RESULTS AND DISCUSSION
DRS ANALYSIS
Samples have been calculated from their DRS plots by
employing Kubelka-Munk function and the approximate
band gap have been evaluated as 2.643eV, 2.704eV and
2.807eV for A,B and C respectively.
Ga conc. increases,absorption of the samples shifts towards
higher wavelength.

11. Fig.8 DRS graph of Ga doped ZnO Fig.9 Kubelka- Munk plot
Ga Conc.
(%mol)
Band gap
(Eg)
(eV)
10% 2.80
15% 2.70
20% 2.64
Table 2

12. Fig.10 Energy Band diagram
Reduction in band gap is due to the repulsion between N2p and Zn3d
energy levels in the valence band.

13. CONCLUSION
Crystalline size, Strain , Bond length , Volume, Lattice
Parameters of the samples with increasing Ga content has
been calculated using XRD Data. As the Conc. of Ga
increases, the Crystalline size decreases and Strain
increases. A shift in the peaks of graph, towards the higher
degree side with increasing Ga content is noticed.
The approximate band gap of the samples have been
evaluated from the DRS plots by employing Kubelka-Munk
function. As the Ga concentration is increased, the
absorption onset of the samples shifts towards the higher
wavelength side, and the Bandgap decreases.

14. THANK YOU…