Band structures and optical properties related to substitutional impurities in TlGaSe2 layered crystals: first-principles study

In this paper, an investigation of the electronic and optical properties of the TlGaSe2 pure layered crystal and TlGaSe2 doped with substitutional impurities in the framework of the density functional theory have been carried out. Based on the calculations of the band structure, energy dependencies for the optical characteristics such as the real and imaginary parts of the dielectric function, the refractive index, and the absorption coefficient were obtained for TlGa1-chi In chi Se2, TlGa(Se1-chi S chi)(2) compounds. The effect of the impurities on the band gap and optical parameters have been analyzed.