Electronic Structure of Type-II InAs/GaSb Superlattices: a DFT+GW Study

Type-II InAs/GaSb strained layer superlattices (T2SLs) are promising candidates for mid-wavelength infrared (MWIR) and long-wavelength infrared (LWIR) applications. Since the bandgap and the band topologies have direct implications on the functionality of electronic devices based on superlattices, it is essential to study the electronic properties of these complex structures. For this purpose, we have investigated the performance of the many-body perturbative method in the GW approximation, to our knowledge for the first time, to study the electronic structure of T2SLs. The structures considered in this study are (4,7), (6,7), (8,8), (10,8), and (10,10) superlattices, denoted by (monolayers of InAs, monolayers of GaSb). Our results predict bandgaps in good agreement with experimental data. The band structure and the electronic density of states, as well as the effective masses along in-plane and growth directions were calculated. Finally, the Bethe-Salpeter equation was used to investigate the absorption spectra of the selected structures.