Ab initio Study of the Structural and Photoelectric Properties of γ-GeSe with B, C and N Adsorption

Using ab initio calculations, the structural and photoelectric properties of γ-GeSe with B, C, and N adsorption were systematically investigated. The atomic structure relaxations show that B, C, and N are preferentially located on the lower hexagonal hollow, upper hexagonal hollow, and on top of Se, respectively. The adsorption with B, C, and N can induce defective bands between the energy region n of the valence bands and the conduction bands, and all the systems with adatoms are magnetic, with 1 μ_B, 2 μ_B, and 1 μ_B magnetic moments, respectively, which are mainly caused by the hybridization between adatoms and the adjacent Ge and Se atoms. Based on the spin-polarized band structure, we find that C-adsorbed γ-GeSe is metallic, while γ-GeSe with B and N adatoms is half-metallic, with 100% spin polarization at the Fermi level. Furthermore, owing to the electronic structural differences between spin-up and spin-down sections of B- and N-adsorbed γ-GeSe, the light in the low-energy region (< 1.0 eV) can only cause electronic excitations in one spin channel, giving rise to interesting spin-polarized photoelectric properties. Our results suggest that γ-GeSe with B, C, and N adsorption is a promising candidate for spintronic photoelectric device applications.