Articles you may be interested inGaAsSb/GaAsN short-period superlattices as a capping layer for improved InAs quantum dot-based optoelectronics Appl. Phys. Lett. 105, 043105 (2014); 10.1063/1.4891557Molecular-beam epitaxy of phosphor-free 1.3 μ m InAlGaAs multiple-quantum-well lasers on InP (100) Midinfrared InGaAsSb quantum well lasers with digitally grown tensile-strained AlGaAsSb barriers Growth of high-quality GaAs/AlAs Bragg mirrors on patterned InP-based quantum well mesa structuresWe identify quasi-donor-acceptor pair transitions in the photoluminescence spectra of GaAsSb and AlGaAsSb layers, lattice matched to InP, and grown by molecular-beam epitaxy. These alloys show compositional inhomogeneity due to phase separation resulting from miscibility gaps. The presence of Al in the quaternary alloy increases the fluctuation of the electrostatic potential in the epitaxial layer, increasing the variation of recombination energy as a function of intensity excitation in the range of low temperatures.