Two-dimensional Bi2Se3 monolayer with high mobility and enhanced optical absorption in the UV–visible light region

Abstract

Abstract To find new two-dimensional materials is continually paid too much attention because of the wonderful properties and potential adhibitions. In the present paper, we report a new Bi2Se3 monolayer based on the first-principles calculation. The geometrical configuration is optimized and the stabilities are affirmed by the phonon dispersion and the ab initio molecular dynamics simulation, respectively. The bandgap and band edges, density of state, optical properties, and mobilities are calculated and analyzed. The effects of strain engineering on the band structure and optical absorption are also explored. The results reveal that the Bi2Se3 monolayer possesses an indirect gap of 1.42 eV(HSE06)/1.96 eV(GW) and can be effectively tuned by the strain. The result of the electronic properties shows that the spatial charge separation of the photogenerated pair of electron and hole is obvious. The Bi2Se3 monolayer is predicted to possess a high electron and hole mobilities of 1.96 × 105(zigzag)/1.6 × 104(armchair) and 3.4 × 104(zigzag)/2.51 × 103(armchair) cm2V−1s−1, respectively. The high optical absorption is observed in the UV–visible light regions and could be affected by the strain. All the obtained results support that the Bi2Se3 monolayer is a prospective material for the optoelectronic, photocatalytic and photovoltaic applications.