B 2 S 3 monolayer: a two-dimensional direct-gap semiconductor with tunable band-gap and high carrier mobility

Abstract Atomically two-dimensional materials with direct band-gap and high carrier mobility are highly desirable due to their promising applications in electronic devices. Here, on the basis of ab initio calculations and global particle-swarm optimization method, we predict the B 2 S 3 monolayer as a new semiconductor with favorable functional properties. The B 2 S 3 monolayer possesses a high electron mobility of 553 cm 2 V −1 s −1 and a direct band-gap of 1.85 eV. The direct band-gap can be manipulated under biaxial strain. Furthermore, B 2 S 3 monolayer can absorb sunlight efficiently in the entire range of the visible light spectrum. Besides, this monolayer holds good dynamical, thermal, and mechanical stabilities. All the desired properties render B 2 S 3 monolayer a promising candidate for future applications in high-speed (opto)electronic devices.