Electronic and optical properties of MoSSe/borophene heterojunctions with the modulation of electric field and vacancy defects

We investigate the electronic and optical properties of MoSSe/borophene heterojunctions by first principles. Two different structures of borophene and several different stacking layers are considered. The heterojunctions of SeMoS/H, SMoSe/H, and SMoSe/beta exhibit the p-type Schottky contacts, while SeMoS/beta presents a n-type Schottky contact. When the external electric field is applied to heterojunctions, the Ohmic contact is achieved for SeMoS/H and SMoSe/H. The introduction of S and Se vacancy defects reduces the Schottky barrier height. The heterojunctions of SeMoS/H-VS and SMoSe/H-VS exhibit the Ohmic contact. Moreover, the optical absorption of heterojunctions with vacancy defects has been significantly enhanced, and SeMoS/beta-VS has the maximum optical absorption coefficient of 2.35 x 104 cm-1. Our results can provide some guidance for the widespread application of two-dimensional heterostructures in tunable nanoelectronics devices.