An alloy semiconductor system with a tailorable band-tail and its application to high-performance laser operation: I. A band-states model for an alloy-fluctuated InGaN-material system designed for quantum well laser operation

摘要

This paper presents a model for a new class of semiconductor-alloy systems for which the band-tail degree can be tailored. The general model is based on experimentally derived data for the InGaN-alloy system. The temperature dependence of the photoluminescence decay time for an InGaN QW structure is fully analysed, verifying the validity of the model in terms of a band-edge state modified by In compositional variation. We found that the band-edge fluctuation can be grown-in between 3 and 170 meV with a single well defined quasi-Fermi level. This model is then used to predict the laser performance for an alloy-fluctuated materials system. We found that the differential gain and the critical carrier density of the inversion distribution are strongly correlated with the fluctuation but in opposite ways. The utilization of alloy fluctuation is very beneficial for a specific laser operation condition if there is sufficient fluctuation optimization. The experimental verification of the model with regards to the laser operation is described in the companion paper (part II).