Unrelaxed bulk InAsSb with novel absorption, carrier transport, and recombination properties for MWIR and LWIR photodetectors

摘要

The optical properties of bulk unrelaxed InAsSb layers having a low temperature photoluminescence (PL) peak up to 10 μm are presented. The materials were grown on GaSb substrates by molecular beam epitaxy. The lattice mismatch between the epilayers and GaSb substrates was accommodated with linearly graded GaAlInSb buffers. An 11-meV width of PL at full-width half-maximum was measured for InAsSb with Sb compositions of 20 and 44%. The best fit for the dependence of the energy gap on Sb composition was obtained with a 0.9-eV bowing parameter. Temperature dependences of the energy gap for InAsSb alloys with 20 % and 44% Sb were determined from PL spectra in the temperature range from 12 to 300 K. A T=77 K minority carrier lifetime up to 350 ns in undoped InAsSb layers with 20% Sb was determined from PL kinetics.