Effects of Si Doping on the Structural, Electronic and Optical Properties of Barium Chalcogenide BaS: A First-Principles Study

Abstract

In this work, the structural, electronic and optical properties of Si-doped barium chalcogenide [barium sulfide (BaS)] with different Si concentrations ([Formula: see text]) are investigated by the first-principles calculations based on the density functional theory (DFT). The band structures, charge densities and complex dielectric functions of the pure as well as Si-doped BaS were presented and analyzed in detail using TB-mBJ approach by WIEN2k package. It is found that silicon concentration can control the bandgap by reducing it to values around 1.4[Formula: see text]eV and 1.6[Formula: see text]eV for 12.5% and 6.25% of Si-doped BaS, respectively. The electron charge density indicates the ionic bonding between silicon and sulfur atoms due to the high electronegativity between them. In fact, the results show that the absorption peaks of Si-doped BaS are enhanced compared with pure BaS. These results suggest that the Ba[Formula: see text]SixS original structure displays excellent physical properties thereby revealing that it is a promising material in advanced optoelectronic and solar cell applications.