Influence of Te doping in InGaAsSb epilayers on the non-radiative recombination time studied by the photoacoustic technique

In this work we present results on the study of the influence of Te doping of InGaAsSb epitaxial layers, grown by the liquid phase epitaxy technique, on the non-radiative recombination times of the epilayers. In the photoacoustic (PA) technique, we use a recently developed model for two-layer semiconductor heterostructures where, taking into account all the possible contributions to the heat generation in the substrate and layer bulks and at the interfaces, we can obtain the non-radiative recombination time of the layer, $\tau_{\rm nr}$, as a fitting parameter of the experimental curves: signal phase vs. excitation frequency fitted to the lineshape of our theoretical model. We present results on the analysis of these PA experimental curves for the set of InGaAsSb layers grown with different Te dopings, showing that the Auger lifetimes decrease by a factor of up to ten-fold when the Te doping in the InGaAsSb layers increases by a factor of about eight; also, from our results we show that the surface recombination velocity increases by a factor of up to 15 due to an increasing roughness of the surface layer as the Te concentration in the layer increases