Effect of bismuth incorporation on recombination mechanisms in GaAsBi/GaAs heterostructures

This paper reports on laser excitation power dependent photoluminescence (PL) studies on epitaxial GaAs 1− x Bi x (2.3% < x < 10.4%) layers with thicknesses of 30–40 nm which are compressively strained onto GaAs substrates. Such materials when used as optical active regions in semiconductor lasers offer the possibility of suppressing the efficiency-limiting Auger recombination losses and improving laser performance in the telecommunication range (1.3–1.5 μm). These experimental investigations on GaAsBi allow us to verify the extent to which GaAs 1− x Bi x provides the optimised band structure as predicted, and secondly to provide the first evidence of the influence of this band structure on optical efficiency and carrier recombination processes. An analysis of the dependence of PL intensity on excitation power was employed to identify the recombination mechanisms in GaAs 1− x Bi x alloys. Temperature tuning the samples with bismuth concentration ~ 8.5% and 1.4% provides tentative evidence for the suppression of Auger recombination losses in this material system highlighting its potential for efficient telecoms laser applications.