Strain-tunable electronics, optics and carrier mobility of Janus Sn2OX (X=S, Se) monolayer

In this work, we have investigated the electronic, optical, and carrier mobility properties of Janus structure Sn₂OX (X = S, Se) monolayer under strain by using the first principles calculations. The results suggest that the band gap decreases with the strain increases, the intrinsic indirect band structure have not been changed. γ-Sn₂OX (X = S, Se) maintained a high light absorption coefficient under strain, the absorption of Sn₂OSe has a blue shift phenomena relative to Sn₂OS. The carrier mobility of γ-Sn₂OX (X = S, Se) decreases with the strain increases mainly due to the relative flatter band structure, smaller elastic modulus and higher deformation potential constant under strain. Fortunately, under about −4 %∼4 % strains, the carrier mobility of γ-Sn₂OX (X = S, Se) does not change greatly, the electron or the hole as major carrier appears in different direction. Our results will provide some theoretical guidance in the design of optoelectronic devices.