Abstract

The electronic properties of InAsSb structures have been characterized by a variety of infrared spectroscopies (absorption, photoluminescence, and magneto-optical) and detector spectral responsivity. In Sb-rich strained-layer superlattices (SLSs), the type II band offset extends the photoresponse to long wavelength when the difference in As composition between SLS layers is 10–20%. Consistent with a type II offset, effective mass measurements reveal that the hole quantum well is located in the biaxially compressed InSb layer of an InAsSb/InSb SLS. As an alternative to Sb-rich, InAsSb SLSs for long wavelength III–V detector structures, we have recently observed significant band-gap reduction in InAs_1−xSb_x(x ≈ 0.4) alloys and SLSs. Ordering on the {111} planes of the group V sublattice (CuPt-type) produces this decrease in band-gap. Prototype infrared detectors and focal plane arrays have been constructed from Sb-rich SLSs. Our best photodiodes were 300 K BLIP limited with detectivities ≥1 × 10¹⁰ cm Hz^1/2/W at wavelengths <10 μm. Prototype detector studies demonstrate that InAsSb SLSs could potentially compete with HgCdTe as a high detectivity, long wavelength photovoltiac detector technology.

© 1992 Optical Society of America