Structural, Electronic, Magnetic and Optical properties of Sm doped ZnS: A First Principle Study

Abstract

Wide band gap semiconductors have many applications in photo luminescence devices and optoelectronic devices. We have investigated the structural, magnetic and optical properties of pure ZnS and Sm doped ZnS using density functional theory and implemented first principle linearized augmented plane wave (LAPW) method. For exchange correlation potential energy, generalized gradient approximation (GGA), GGA+U (where U is Hubbard potential) and Trans and Blaha modiefied Becke-Johnson (TB-mBJ) approximations are used. ZnS is a wide band gap semiconductor material having experimental band gap ~ 3.54eV. In this study band gap of pure ZnS was calculated as 1.963eV, 2.124eV and 3.574eV by using GGA, GGA+U and TB-mBJ approximations. GGA+U approximation was used for spin polarized calculations of ZnS: Sm shows ferromagnetic (FM) behaviour of doped semiconductor with band gap is 2.75eV. Pure ZnS is isotropic material while after doping with Sm it becomes anisotropic material. Ultraviolet and visible radiations are absorbed in these materials hence they can have potential applications in optoelectronic devices.