Recent advances in In(As, Sb) SLS and QW LED's for the 3-10 micron region

InAs/In(As,Sb) heterostructure LED's are studied in forward (FB) and reverse (RB) bias where the phenomenon of negative luminescence is seen for the first time in this materials system. Pseudomorphic 300K SQW LED's, lattice matched to InAs and emitting at γ∼5μm and γ∼8μm, have internal conversion efficiencies of >1.3% and >0.83% respectively and maximum outputs in excess of 50 μW, in spite of an extremely low overall epilayer Sb content. Strain-relaxed InAs/In(As,Sb) SLS LED's with A1Sb barriers for electron confinement give 300K outputs in excess of 0.1mW at γ∼4.2μm,. ∼3.5 times greater than control devices without the AlSb barrier. In RB the same SLS diodes exhibited efficient (∼14%) negative luminescence with output powers which increase with increasing device temperature to within 0.8 of the FB figures at 320K.