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

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-edg e 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 defin ed quasi-Fermi level. This model is then used to predict the laser performa nce for an alloy-fluctuated materials system. We found that the differentia l gain and the critical carrier density of the inversion distribution are s trongly correlated with the fluctuation but in opposite ways. The utilizati on of alloy fluctuation is very beneficial for a specific laser operation c ondition 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).