nBn HgCdTe infrared detector with HgTe(HgCdTe)/CdTe SLs barrier

Abstract

Several strategies have been implemented to improve the performance of infrared single pixel detectors at higher operating temperature condition. The most efficient and effective in HgCdTe technology are: non-equilibrium architectures and currently an idea of the barrier detector to include unipolar and complementary structures. Valence band offset between active layer and barrier impeding the minority carrier transport is considered to be the most important issue to overcome. Currently, implementation of the Cd composition and doping graded interfaces has been proposed. In this paper we present the performance (dark current, detectivity, time response) of the nBn detector with HgTe(HgCdTe)/CdTe superlattice barrier. The superlattice barrier is believed to decrease valence band offset between active and barrier layers. Theoretically estimated detectivity of mid-wave (cut-off wavelength, 4.8 μm) detector is ~3×1012 cmHz1/2/W and time response 150 ps for zero valence band offset, bias 2 V and temperature 155 K.