Strong terahertz absorption in long-period InAs/GaSb type-Ⅱ superlattices with inverted band structures

摘要

We present a theoretical investigation on the terahertz (THz) absorption by long-period InAs/GaSb type-Ⅱ superlattices (SLs) with inverted band structures. It is found that in such SLs the band inversion causes a significant electron-hole hybridization and a strong THz absorption can be induced by this hybridization. The THz absorption coefficient is even larger than mid-infrared absorption coefficient for short-period InAs/GaSb SLs. Moreover, we find that the strong THz absorption can be further improved and optimized by the proper choice of InAs/GaSb layer widths. The interesting absorption features are well manifested in hybridization gaps and optical transition matrix elements. This study is pertinent to the potential application of long-period inverted InAs/GaSb type-Ⅱ SLs as high-efficiency THz photodetectors.