Investigation of the recombination dynamics in low in-content InGaN MQWs by means of cathodoluminescence and photo-luminescence excitation

In this work we present a detailed optical characterization of InGaN-based multiple QWs performed by combining time-resolved and time-integrated photoluminescence and cathodoluminescence techniques. The experimental results are well reproduced in the framework of a theoretical model where a self-consistent solution of Schrodinger-Poisson equations is coupled to a rate equation model to account for time-dependent effects of charge re-arrangement to determine the electronic states in the nanostructure. The theoretical model is demonstrated to describe in a common scenario either time-integrated and time dependent photoluminescence and finally cathodoluminescence, for samples having different well widths (i.e. different internal polarization fields). We demonstrate that, provided the correct material parameters of the InGaN/GaN alloys are considered in the model, including the bowing of the polarization fields and Gap, the same theoretical approach previously reported for AlGaN/GaN systems applies.