2.4 - Electro-Optical Properties of InAs/GaSb Superlattice Infrared Photodiodes for Bispectral Detection

InAs/GaSb shortperiod superlattices have proven their large potential for highperformance focal plane array infrared detectors. They are fabricated as monospectral and bispectral infrared detectors for a wavelength range between 3�30 !m with very high responsivity and thus comparable to stateof� theart CdHgTe and InSb detectors. Dualcolor, midwavelength infrared InAs/GaSb superlattice camera systems offer simultaneous and spatially coincident detection on a millisecond time scale in both spectral channels between 3�4 !m and 4�5 !m. Thus, these cameras are very sensitive to the spectral signature of carbon dioxide at approximately 4.3 !m and can be used for remote imaging of CO2. In a molecular beam epitaxy based process, eleven 288 × 384 dualcolor detector arrays are fabri cated on 3 GaSb substrates. Very homogeneous detector arrays with an excellent noise equivalent temperature difference have been realized. This article presents the InAs/GaSb typeII superlattice dualcolor concept, its results, and delivers insights into a range of test methodologies which ensure that the basic requirements for achieving high detector performance are fulfilled.