Dynamics of the spontaneous emission factor in multiple quantum well nanowire lasers

Abstract

The spontaneous emission factor - often known as the \b{eta} factor - is an important quantity in the description of quantum well lasers, influencing both the threshold power as well as the general shape of the light in-light out (L-L) curve. Past work on modelling multiple quantum well (MQW) nanowire laser devices has typically assumed that the \b{eta} factor is a constant parameter that can either be estimated or fit in a post-hoc manner. However, the \b{eta} factor can be derived from the transitions between valence and conduction bands in semiconductor quantum wells, together with knowledge of the cavity modes. Here we investigate the dynamic nature of the \b{eta} factor for MQW nanowire lasers, and show how it can be computed. We also examine the dependence of the spontaneous emission rate and spontaneous emission factor \b{eta} on the charge carrier density, quantum well thickness, and composition, and discuss the impact on laser threshold and operation.