Kodan, Nisha and Auluck, S. and Mehta, B. R. (2016) A DFT study of the electronic and optical properties of a photovoltaic absorber material Cu2ZnGeS4 using GGA and mBJ exchange correlation potentials. Journal of Alloys and Compounds, 675. 236-243. ISSN 0925-8388

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Abstract

The electronic and optical properties of Cu2ZnGeS4 are calculated by means of the full potential linearized augmented plane wave method (FP-LAPW) using the generalized gradient approximation (GGA) and the modified Becke-Johnson (mBJ) as exchange correlation functionals. The band structures, total and partial densities of states as well as optical properties are presented and discussed in the context of the available experimental data and theoretical calculations. Our calculations show that the conduction bands minima (CBM) is composed of contributions mainly from Ge-p states while the valence bands maxima (VBM) is dominated by Cued states. We find that Cu2ZnGeS4 possesses a direct energy band gap situated at the center (Gamma point) of the Brillouin Zone (BZ). The calculated energy gaps of 0.50 eV (GGA) and 1.21 eV (mBJ) are much smaller than the experimental value of around 2.2 eV. We have shown anisotropic behavior of the compound using optical constants and birefringence plots and found that the Delta n(0) in GGA and mBJ is about 0.06 and 0.08, respectively when applied scissors correction. We find that applying the scissors correction leads to better agreement with the experiment.

Item Type:	Article
Additional Information:	Copyright for this article belongs to M/S Elsevier B.V.
Uncontrolled Keywords:	Semiconductors Optical properties Computer simulation (DFT) Intermetallics
Subjects:	Chemistry > Physical Chemistry Materials Science Metallurgy & Metallurgical Engineering
Divisions:	UNSPECIFIED
Depositing User:	Dr. Rajpal Walke
Date Deposited:	02 Jun 2017 07:41
Last Modified:	02 Jun 2017 07:41
URI:	http://npl.csircentral.net/id/eprint/2132

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