B₂S₃monolayer: a two-dimensional direct-gap semiconductor with tunable band-gap and high carrier mobility

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 ofab initiocalculations and global particle-swarm optimization method, we predict the B₂S₃monolayer as a new semiconductor with favorable functional properties. The B₂S₃monolayer possesses a high electron mobility of 553 cm²V^-1s^-1and a direct band-gap of 1.85 eV. The direct band-gap can be manipulated under biaxial strain. Furthermore, B₂S₃monolayer 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 B₂S₃monolayer a promising candidate for future applications in high-speed (opto)electronic devices.