Electronic and transport properties of GaAs/InSe van der Waals heterostructure

摘要

Recently, the GaAs/InSe heterostructure was synthesized experimentally, and the spatial redistribution of charge and motion of energy-resolved photoelectron was imaged. To gain more insight into the detailed electronic structure and expand knowledge to transport behaviors and physical field tuning effects, we here construct the GaAs/InSe van der Waals heterostructure theoretically and perform investigations in depth, especially focusing on the comprehensive understanding and mechanism analysis of results, trying to create new predictions. The results show that such a heterostructure holds a typical type-II band alignment and its band gap is narrowed significantly as compared with its each component, and the indirect-direct band gap transition is realized, which holds great potential applications in developing excellent photovoltaic materials and new photo-electronic devices. Particularly, the carrier mobility of heterostructure is predicted to be enhanced dramatically to mu 10(4) cm(2) V-1 s(-1), greatly overcoming the intrinsic weakness of InSe monolayer with a very low hole mobility, similar to 10(1) cm(2) V-1 s(-1). Meanwhile, we find that the electronic structure of the heterostructure is flexibly controllable. Under higher compressive strain and whole tensile strain, its band-gap size drops linearly. While by applying an external electric field, the band offset is increased significantly, and the type-II band alignment is well preserved and the band gap drops significantly under positive external electric field, These flexibly tunable properties are more favorable to design the photovoltaic materials and photo-electronic devices.