Type-II InAs/GaSb Superlattice Detectors and Focal Plane Arrays in the Very-Long Wavelength Infrared Range

"Photon detectors presently available in the very long wave infrared range (lambda > 15 ¿m) are based on extrinsic silicon and HgCdTe. Due to excessive dark current, the operating temperature of these detectors is below 20K. At present, the most promisingalternative is III-V compound semiconductor superlattices based on arsenides and antimonides, such as type-II InAs/GaSb. It is here proposed to develop improved and innovative epitaxial growth techniques for growing such superlattices with much reducedspitting defect density through, in part, the use of newly available effusion cells for the gallium and indium sources in molecular beam epitaxy (MBE). Type-II InAs/GaSb superlattices will be grown and characterized. Large area type-II InAs/GaSbsuperlattice detectors will be grown, fabricated and tested in order to evaluate the technical and commercial viability of the proposed approach. Upon successful achievement of the proposed work, it is anticipated that higher quality and uniformity type-IIInAs/GaSb superlattice infrared material will be available. High performance large area single-element detectors based on this material system, operating beyond 15¿m and at temperatures above 40K, will be demonstrated. This will in turn enhance theprospect of focal plane arrays exhibiting similar operational characteristics for space-based applications, including long range missile threat warning, pollution monitoring, and astronomy. The