Efficient 300 K light-emitting diodes at λ∼5 and ∼8 μm from InAs/In(As1-xSbx) single quantum wells

300 K light-emitting diodes which emit at 5 and 8 mu m with quasi-cw output powers of up to 50 and 24 mu W, respectively, are reported. The devices have a single molecular beam epitaxy grown InAs/In(As, Sb) quantum well in the active region with a strong type-IIa band alignment giving mid-IR emission at energies up to 61 % lower than the alloy band gap. The emission energies are shown to be in good agreement with a k.p bandstructure model where Q(c), the ratio of the strained conduction-band offset to the band-gap difference between the two strained superlattice components, is found to be similar to 2.0. (C) 1998 American Institute of Physics.