Calculation of tunable optical and electronic properties of two-dimensional AlSb/BAs heterojunction based on first principles

In this study, the geometrical properties of AlSb/BAs heterojunction is calculated using the first principles of Density Functional Theory (DFT). It is concluded that the H1 AlSb/BAs heterojunction are the most stable when the layer spacing of the heterojunction is 3.423 angstrom. By investigating the electronic properties of the H1 AlSb/BAs heterojunction, it is found that the heterojunction has a direct band gap of 0.490 eV and it has a Type-II band arrangement. By applying electric field and strain to the H1 AlSb/BAs heterojunction, it is spotted that the band gap size of the heterojunction is altered. Moreover, applying electric field and stress causes the heterojunction to change from Type-II band arrangement to Type-I band arrangement, which enables the H1 AlSb/BAs heterojunction to be applied not only in the field of photodetectors but also in the field of light-emitting diodes. Investigating the optical properties of AlSb monolayer, BAs monolayer and H1 AlSb/BAs heterojunction, it is uncovered that the optical absorption coefficients of H1 AlSb/BAs heterojunction (1.103 x 10-6 cm-1) are higher than those of the two monolayers on the whole. At the same time, the application of the applied electric fields and stress can effectively regulate the optical properties of AlSb/BAs heterojunction.