Intrinsic defects in gallium sulfide monolayer: a first-principles study
The electronic and magnetic properties of native point defects, including vacancies (VGa and VS), antisites (GaS and SGa) and interstitials (Gai and Si) in monolayer and bulk GaS, were systemically studied using the density functional theory method. For the monolayer, the impurity states appeared in the band gaps of all defect structures except interstitial Si. Half-metallic behavior can be obtained in the presence of VGa and Gai. Monolayers with VGa, GaS, SGa and Gai had a total magnetic moment of 1.0 μB, as did the bulk samples with VGa, GaS and SGa, whereas the monolayers with VS and Si and bulk sample with Gai were spin-unpolarized. In addition, n- and p-type GaS monolayers were obtained under Ga-rich and S-rich conditions, respectively. GaS and SGa were identified as suitable n- and p-type defects, respectively.