Optical Properties of α-Se Revealed by ab initio Calculations

Abstract

Abstract Detailed optical functions and optical properties of a α-monoclinic phase of Selenium α- Se are presented over a wide range of angular frequencies ωby first-principles calculations. An optical band gap of 2.05eV and a mobility gap of 2.17eV ±0.05 are observed in the present calculations. The imaginary part of the dielectric function has been obtained from the frequency dependent dielectric matrix and the use of the Kramers-Kronig (KK) relation allows us to determine the real part of the dielectric function. Optical functions and optical properties revealed the occurrence of a long range order in Se. For the first time, infrared and absorption spectra of monoclinic -Se were studied using the Kramers-Kronig (KK) relation by ab initio method. And lastly, detailed studies of other dielectric related optical constants such as reflectivity, transmission, reflection and absorption coefficients were also presented.