Tunable bandgap and vacancy defects in GaSe/SnSe van der Waals heterostructure

Herein, GaSe/SnSe van der Waals heterostructure is established based on first-principles calculations of density functional theory (DFT). And the changes of band structure, bandgap, density of states, electronic density difference, and optical properties of GaSe/SnSe heterostructure before and after the introduction of Ga, Sa1, Sn, and Se2 vacancies are systematically studied. The results show that GaSe/SnSe heterostructures and four vacancy heterostructures can exist stably. The band structure of GaSe/SnSe heterostructure changes greatly with the introduction of vacancy. When Ga vacancy is introduced, the GaSe monolayer and GaSe/SnSe heterostructure exhibit obvious metal properties. In addition, the introduction of vacancies makes GaSe/SnSe heterostructures available for ultraviolet and visible light absorption and conversion. The introduction of vacancies in GaSe/SnSe heterostructures provides a feasible strategy for adjusting the photoelectric properties of two-dimensional photoelectric nanodevices. It has good potential and broad application prospects in infrared light conversion and detection.