RECENT ADVANCES IN GA1-XINXSB INAS SUPERLATTICE IR DETECTOR MATERIALS/

Development of Ga1-xInxSb/InAs superlattices has been motivated by pot ential applications to infrared (IR) detectors in the 8-12 mu m band a nd the far IR region 12-20(+) mu m. Theoretical and experimental resul ts to date support the prospect that very high performance III-V mater ials-based IR focal plane array (FPA) sensors that can operate at temp eratures higher than HgCdTe photovoltaic devices are feasible. The het erostructures under development are grown by molecular beam epitaxy (M BE) and are type-II, broken gap superlattices of alternating layers of Ga1-xInxSb/InAs with compositions chosen to allow the superlattice to be symmetrically strained to GaSb substrates. The details of the inte rface structure at the GaSb surface, the character of the interfaces b etween the Ga1-xInxSb and InAs layers, and the chemical nature of the Group V flux used in the MBE growth process are among the critical fac tors in enabling the growth of superlattices of extremely high optical quality suitable for IR detectors. We review recent advances in the m aterials and epitaxial processes for growing these superlattices. Thes e processes have been applied to producing IR detector structures tail ored to the particularly difficult spectral range of very long wavelen gth cut-off of 12(+) mu m. (C) 1998 Elsevier Science B.V.