Theoretical design and electronic properties study of two-dimensional Si2S

The zero band gap and air instability seriously of silicene limit its application in logic devices. By introducing the group VI elements, the band gap and stability of silicene will be adjusted. In this research, we propose a new two-dimensional material, Si2S. Si2S has excellent dynamic stability and thermal stability. AIMD simulations show that Si2S can maintain structural integrity at a temperature of 600 K. Si2S has an indirect band gap of 1.93 eV. The indirect band gap can be transformed into a direct band gap under the uniaxial strain along x direction or biaxial strain. The calculated carrier mobility of Si2S is anisotropic and the highest carrier mobility of Si2S is 182.72 cm2 V−1 S−1. The band gap and carrier mobility of Si2S are comparable with that of monolayer MoS2, which makes it promising to be used in the field of nanoelectronics.