Infrared Detectors Based on GalnSb/InAs Superlattices

Abstract

Both superlattice and multi-quantum well (MQW) structures have been proposed as alternatives to conventional infrared (IR) detector materials. Optical absorption selection rules often dictate use of diffraction gratings in the MQW detectors. No such measures are required in the superlattice. In either case, IR detection arises from a photocurrent associated with drift or diffusion of photo-excited carriers. The capability to tailor the properties of superlattices through choices of layer thicknesses and compositions has prompted work on several III-V and II-VI systems. While superlattices afford greater freedom of device design than alloys, it is clearly impossible to simultaneously optimize all properties of importance. It is hoped that a mature GalnSb/InAs technology would benefit not only from improved performance, but also from advantages of III-V semiconductors over II-VI’s. A clear advantage of a successful GalnSb/InAs detector would be use of conventional III-V processing techniques, leveraging off a technology developed for a wide variety of electronic and optoelectronic devices.