Comparative advantages of a type-II superlattice barrier over an AIGaSb barrier for enhanced performance of InAs/GaSb LWIR nBn photodetectors

Abstract

The barrier layer in InAs/GaSb LWIR nBn detector is usually composed of AIGaSb alloy, which has a non-negligible valence band offset and is sensitive to chemical solutions. In this work, we investigated a type-H superlattice (T2SL) barrier that is homogeneous with the T2SL absorber layer in order to resolve these drawbacks of the AIGaSb barrier. The lattice mismatch of the T2SL barrier was smaller than that of the AIGaSb barrier. At -70 mV and 80 K, the dark current density and the noise equivalent temperature difference of the nBn devices with the T2SL barrier were 4.4 x 10(-6) A/cm(2) and 33 mK, respectively. (C) 2021 Optical Society of America