Co-Located Dual Band (VLWIR1/VLWIR2) Focal Plane Arrays for Space Applications

"We propose to develop Co-Located Dual Band (VLWIR1/VLWIR2) Focal Plane Arrays on Strained Layer Superlattices (SLS) Material. We propose innovative Al(x)Ga(1-x)As/InAs SLS layers to produce detectors for very long wavelength (22 um). The key features are:1) SLS Material Growth by Migration Enhanced Epitaxy (MEE) Technique. Type II SLS layers are grown with Migration Enhanced Epitaxy Technique by using a Molecular Beam Epitaxial (MBE) reactor.2) SLS Structures for VLWIR Waveband. Detailed analysis is conducted by using 8-band k.p. model to design SLS structures for Very-Long Wavelength (22um) detection.3) Co-Located Dual Band (VLWIR1/VLWIR2) SLS Structures. Co-Located SLS Structures are grown for VLWIR1 (10-16um) and VLWIR2 (16-22um) waveband ranges with Al(x)Ga(1-x)As/InAs SLS layers.4) Simultaneous Detection of Dual Band Signals. The readout circuitry and the interconnect scheme are designed to detect the two waveband signals in a simultaneous fashion during each frame.5) Cross Talk Elimination. The design of the 2-color structure is such that the cross talk among the wave bands and also among the pixels are eliminated.High Performance Al(x)Ga(1-x) As/InAs dectors were already fabricated and tested for SWIR(1-3um) waveband. The results showed: Detectivity (cm-Hz(1/2)/W)=1.3E12 at 77K, 1.4E11 at 250K, 2E10 at 300K, and quantum efficiency (n) = 72%During Phase 1, the growth of Al(x)Ga(1-x)Sb/InAs SLS structures will be optimized and