Structural and electronic properties of substitutionally doped SiAs monolayer

The substitutional single-atom doping is proven to be a significant method to alter the electronic properties of low dimensional materials. Based on the first-principles density functional theory, we present a systematic study on the structural and electronic properties of single-atom substitutionally doped SiAs monolayers. SiAs monolayer is a semiconductor with an indirect band gap of 1.6 eV. Through substitutional doping, the band gap (calculated at the PBE level) of the monolayer SiAs ranges from 0.032 eV to 1.625 eV. The Si31XAs32 (X = B, Al, Ga) and Si32As31Y (Y = C, Ge, Sn) systems present magnetic ground states with a magnetic moment of 1.00 mu B. Moreover, monolayer Si31XAs32 (X = B, Al, Ga) and Si32As31Y (Y = C, Ge, Sn) have long range and local short range magnetic moments owing to the degree of hybridization between the dopant and its adjacent atoms. Metallic behavior can be found in Si31XAs32 (X = N, P, Sb), Si32As31Y (Y = O, S, Se) systems due to the contribution of doped atoms intersecting the Fermi level. The calculated results could provide a new approach for low dimensional doped SiAs-based photoelectronic and magnetic semiconductor devices.