1
Department of Physics, Faculty of Science,ShahidChamran University,of Ahvaz,Ahvaz,Iran
2
Department of Physics, Faculty of Science, ShahidChamran University of Ahvaz,Ahvaz,Iran
Abstract
In this paper, the optical properties of Na2S in various fcc, orthorhombic and hexagonal structural phases have been investigated. Calculations have been performed by using wien2k package which is based on density functional theory and FP-LAPW method. The LDA band structure calculation indicate that Na2S is a direct band gap semiconductor in each three studied phases. The optical band gaps obtained from imaginary part of dielectric function are in good agreement with structural band gaps. According to our results the maximum peak of the imaginary part of dielectric function, occurred at the energy range which coincide to the maximum peak of obsorbation and extinctions curves on that range. Similar behavior is observed for real part of dielectric function in comparison to refraction and reflections diagrams.
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