An Ab Initio Study on the Properties of Sb-Rich GaBi_xSb_1−x

GaBi_xSb_1−x has been considered as a technologically important III–V semiconductor alloy for its potential applications in mid-infrared and near-infrared devices. So far, we still know little about the properties of the Sb-rich GaBi_xSb_1−x. In order to better understand it, first-principles calculations have been performed. A more accurate lattice constant of GaBi has been obtained in this work, and its value was 6.275 Å. After fitting the calculated lattice constant of GaBi_xSb_1−x, it yields \(b = 0.011\) $b=0.011$ Å. Based on the band structures and the partial densities of states of GaBi_xSb_1−x, it has been found that the initial Bi level lies 1.0 eV below the valence band maximum (VBM) of GaSb at the G point. It has also been found that the highly localized Ga-3d peak can be used to ascertain the valence band offset between GaSb and GaBi. According to the location of the localized Ga-3d peak, the valence band offset between GaSb and GaBi was 0.42 eV. In addition, the direct band gap energy in the Sb-rich range decreases quickly due to the rise of the VBM and the decline of the conduction band minimum. For the sake of describing the band gap energy, a combination of a linear equation and the fusion-repelling model is proposed.