New Raman Spectrometer of CSIR-NPL for the Advanced Characterization of the Novel Materials
Volume: 3 - Issue: 04 - Date: 01-04-2014
Approved ISSN: 2278-1412
Published Id: IJAECESTU227 | Page No.: 317-323
Author: Sugandha Dogra Pandey
Co- Author:
Abstract:-A new Raman spectrometer with options to go down to low temperatures of 4.2 K and
high pressure up to 20 GPa has been installed recently. The spectrometer was calibrated using
various standard reference materials e.g. silicon, diamond and Ge etc. A large number of samples
both at room temperature and at low temperatures have been studied. We shall be reporting here
Raman Spectroscopic studies of five technologically novel materials at room temperature namely
GaN, Cu2ZnSnS4
(CZTS), Doped Lithium Niobate (LiNbO3), YVO4
[Eu+3, Sm+3] and finally Sb2Te3
.
For low temperature studies, we have selected Sb2Te3 up to 77 K. We have analyzed the results
from the theoretical estimation of optical phonons which are described by the irreducible
representation of the crystal structures and then compared these with the experimental data. For
low temperature studies, the temperature dependent Raman frequency shift has been studied. The
systematic shifts have been explained in light of the thermal expansion and anharmonic phononphonon interactions. In both these studies [room & low temperatures], close agreements between
the theoretically obtained data with the experimentally obtained Raman modes or shift are very
encouraging.
Key Words:--
Area:-Engineering
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