InAs/InAs(P,Sb) quantum-well laser structure for the midwavelength infrared region

Strained InAs1−xSbx(0<x<0.22) quantum wells with InAs, InAsP, or InAsPSb barrier layers have been grown by metal–organic vapour-phase deposition on InAs substrates. Their photoluminescence and electroluminescence were studied at 20 K. The photoluminescence peak-wavelength evolution with the antimony composition x and the nature of the barrier were theoretically predicted in a satisfactory manner under the assumption of a type-II band alignment for the InAsSb/InAs system with a valence band ratio Qv=−1.30. This hypothesis leads to a type-IIa band alignment for the arsenic-rich InAsSb/InAsP system. Starting from this result, a `W' laser structure, consisting of ten periods of InAsSb/InAsP/InAsSb/InAsPSb multiquantum wells in the active region, a broadened InAsPSb waveguide, and AlAsSb cladding layers, is proposed for room-temperature emission near 3.3 μm.