Electronic and optical properties and device applications for antimonene/WS2 van der Waals heterostructure

Abstract

The antimonene and WS2 monolayers have widely studied recently. Here, we construct the Sb/WS2 van der Waals heterostructures to explore their combined effects on electronic and optical properties based on density functional method. The calculated results show that the most stable heterostructure is a type-Ⅱ semiconductor with a medium band gap of 1.183 eV. The external electric field can alter its band gap significantly, for example, the small negative electric field can make the band gap narrowed sharply and linearly. Based on this behavior, a high-performance heterostructure Schottky-barrier field effect transistor is designed. And under vertical strain, the heterostructure is robust to sustain a type-Ⅱ band alignment, but the band gap can be reduced rapidly by pressure. Accordingly, a strain-gated high switch-ratio mechanical switch device by working reversibly between the “compressive” and “unstrained” states is suggested. Also shown is that this heterostructure prefers the visible light adsorption, and the photoelectric power conversion efficiency (PCE) is as high as 20.98%. Particularly, under small positive electric field, the light adsorption and PCE for this heterostructure is enhanced significantly up to 22.845%. Thus a photovoltaic cell with a high PCE is proposed.