Abstract

Strained-layer superlattices (SLSs) made of alternating layers of InAsSb have recently been proposed as alternative III–V materials for infrared detector applications in the 8–12-μm wavelength range.¹ The wavelength cutoffs of certain SLS structures in this material system are theoretically predicted to be extendable to 12 μm through the effects of the elastic layer strains in the InAs-rich layers. These III–V materials are expected to be more stable than the HgTe-rich HgCdTe alloys due to the greater bond strengths of the III–V materials. However, the use of superlattices as photovoltaic detector materials introduces new considerations for the design of high efficiency devices. In particular, superlattices typically exhibit minority carrier diffusion lengths along the growth direction which are less than one-tenth of the in-plane diffusion lengths.² This paper reviews the issues involved in tailoring the wavelength cutoff of infrared superlattice materials and designing efficient photovoltaic detector structures using these materials.

© 1986 Optical Society of America