Band structures for short-period (InAs)n(GaSb)n superlattices calculated by the quasiparticle self-consistent GW method

We apply a hybrid quasiparticle self-consistent GW (QSGW) method, QSGW80+ SO [Deguchi et al., Jpn. J. Appl. Phys. 55, 051201 (2016)], to a type-II superlattice, which is (InAs)(n)(GaSb)(n) (n = 1, 2, 3, and 4) for infrared sensors. For the first time, we successfully obtained reliable energy bands of the superlattice. The calculated band gaps as functions of n differ from those obtained on the basis of other theories, although they are consistent with the results of a recent photoluminescence experiment. Our real-space analysis of band-edge alignment obtained via core levels shows that the calculated band offset of InAs/GaSb for n = 4 is similar to 0.5 eV, which is consistent with the value obtained in an X-ray photoelectron spectroscopy experiment. (C) 2017 The Japan Society of Applied Physics