Strain and external electric field modulation of the electronic and optical properties of GaN/WSe2 vdWHs

Recently, the GaN/WSe2 van der Waals heterostructures (vdWHs) were successfully synthesized in experiments, providing a pathway for designing the nitride semiconductor materials with transition metal dichalcogenides (TMDs) heterostructures. To insight into the physical mechanism of the GaN/WSe2 vdWHs, the geometrical, electronic and optical properties of the systems are examined based on the first-principles calculations. Our results indicate that the GaN/WSe2 heterostructures exhibit typical type-I band alignment with the bandgap values around 2.20 eV at HSE06 level. Biaxial and external electric field not only can cause the evolution of the band alignment to transfer from type-I to type-II, but also can realize semiconductor-metal transition. In addition, compressive strain enhances the light absorption intensity in the ultraviolet region and tensile strain enables the GaN/WSe2 vdWHs to appear a distinct peak in infrared (IR) region. These flexible and tunable characteristics of type-I GaN/WSe2 vdWHs are more convenient for the design of IR detectors, photovoltaic and light emission devices.