Structural and optical properties of SbxSe100−x (x = 0, 5) thin films

Abstract

We studied the structural and optical properties of SbxSe100−x (x = 0 and 5) thin films (thickness ~320 nm) deposited by thermal evaporation. The structural properties and stoichiometry of prepared samples were studied by X-ray diffraction and energy dispersive X-ray spectroscopy, respectively. With Sb addition, average coordination number increased and number of lone pair of electron, cohesive energy, fraction of floppy modes decreased. The transmission spectrum (450–2700 nm) was used to calculate the thickness, refractive index and extinction coefficient by Swanpoel’s method. Refractive index and extinction coefficient were used to obtain linear and non linear optical parameters. The refractive index, extinction coefficient, volume energy loss function, surface energy loss function, dielectric constant, dielectric loss function, optical conductivity and non-linear optical parameters increased with Sb doping to a-Se. The increase in optical parameters was due to decrease in optical band gap. The decrease in optical band gap was due to increase in density of localized states in mobility gap. The results revealed that with addition of Sb, the system becomes more stable, relaxed and rigid.