Molecular beam epitaxy grown AlAsSb/GaAsSb distributed Bragg reflector on InP substrate operating near 1.55 μm

Surface normal optoelectronic devices operating in the 1.3--1.5 μm wavelength range require distributed Bragg reflectors (DBRs) with a practical number (≤50) of mirror layers. This requirement implies a large refractive index difference between the mirror layers, which is difficult to achieve in the traditionally used phosphide compounds. For the first time, an AlAsSb/GaAsSb DBR grown nominally lattice matched to an InP substrate by molecular beam epitaxy is demonstrated. Reflectivity measurements indicate a stop band centered at 1.53 μm, which is well fitted by these theoretical predictions. Atomic force microscopy and transmission electron microscopy indicate reasonable crystal quality with some defects due to an unintentional lattice mismatch to the substrate