CHEM01200604004 Shri Sanyasinaidu Boddu - Homi Bhabha ...

the compounds shows similar characteristics, except the broadening and shifting of the band
position corresponding to Ga-O vibrations to higher wave numbers with increase in precursor
concentration. Again based on the same logic mentioned in the previous section, this has been
attributed to the reduction in the particle size with increasing the concentration of the
reactants
% of Transmittence
80
60
40
20
1.44 mmol Ga
2.88 mmol Ga
22.96 mmol Ga
400 600 800 1000 1200
Wavenumber(cm -1 )
Fig.95. FT-IR spectra of ZnGa 2 O 4 nanoparticles prepared with different amounts of starting
material.
In order to check the morphology of these nanoparticles, TEM measurements for
representative samples have been carried out and the images are shown in Fig.96. TEM
measurements (Fig.96 (a)) revealed that samples prepared with 1.44 mmol Ga and 0.72 mmol
Zn consist of particles with diameter around 4-6 nm. The distance between the lattice fringes
from HRTEM image (Fig.96 (b)) has been measured and found to be matching with that of
(311) plane of crystalline ZnGa 2 O 4 phase. Concentric rings in SAED pattern (Fig.96 (c)) also
confirm nanocrystalline nature of the sample. The TEM image of sample prepared with 22.96
mmol of Ga and 11.48 mmol of Zn is shown in Fig.96 (d). From the image, presence
nanoparticles having size in the range of 2-3 nm can be confirmed. The corresponding
HRTEM (Fig.96 (e)) and SAED pattern (Fig.96 (f)) further confirm the smaller size of the
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