Strain regulation of the photoelectric performance of 2D InSe-AlAs vdW heterojunction: a DFT study

Two-dimensional van der Waals heterojunctions (vdWs) have already garnered extensive and significant attention due to the excellent properties of smooth heterointerface, tunable band gap, and high carrier mobility. Inspired by the successful formation of vdWs heterojunctions, the electronic structure and photoelectric properties of devices based on InSe-AlAs vdW heterojunction are deeply and systematacially studied by using density-functional theory combined with the non equilibrium Green's function approach. Six special configurations of InSe-AlAs vdW heterojunction were established by translational sliding InSe on AlAs monolayer, and the AA stacking model was identified as the most stable stacking structure. After the introduction of the horizontal and vertical strains, we observed that the band gap value continued to decrease with increasing the compression or tensile conditions. Further investigating the light absorption properties of the InSe-AlAs heterojunction under different strains, it found that an excellent light absorption characteristics with a wide and strong absorption peak within the UV range, especially at the light absorption coefficient can be up to 105. Finally, a nanodevice based on InSe-AlAs vdW heterojunction is designed to analyze the strain-induced photoconductivity changes, and the vertical strain could effectively regulate the photocurrent peaks. Therefore, electronic and photoelectric properties of vdW heterojunction can be highly tuned by tuning applied extra strains. This research will help expand the application of InSe-AlAs heterojunctions in the field of optoelectronics, and provide a theoretical basis.