Calculation of tunable electronic and optical properties of AlSb/CdSe heterojunction based on first principles

Abstract

The geometric structure, electronic and optical peculiarities of AlSb/CdSe heterojunction were investigated based on the first principles computation of Density Functional Theory (DFT). It is detected that the A1-type AlSb/CdSe heterojunction with a layer spacing of 3.218 Å has the most stabilized structure. The heterojunction has a smaller band gap than two monolayers, which facilitates the excitation of photogenerated electrons. The heterojunction also pertains to Type-Ⅱ heterojunction, which is helpful for the separation of photogenerated electrons and hole pairs. A1-type AlSb/CdSe heterojunction also has higher Ultraviolet light (UV) absorption coefficient, which has good application value in the field of UV detectors. By applying electrical field and stress to AlSb/CdSe heterojunction, it is spotted that can efficaciously modulate the band gap of heterojunction, the orientation and amount of electron transfer, and make heterojunction transform from Type-Ⅱ to Type-Ⅰ, so that the heterojunction can not only be applied in the field of the photoelectric detector but also be used in laser and other fields. The applied electrical field and stress can rise the optical absorption coefficient of the heterojunction, and make the absorption spectrum of the heterojunction appear blue or red shift, which can adjust the optical peculiarities of the heterojunction.