Alloy semiconductor system with tailorable band-tail: A band-state model and its verification using laser characteristics of InGaN material system

In this paper, we present a model for a new class of semiconductor alloy sy stems that have a tailorable band-tail. The model is constructed from exper imentally derived data on the InGaN alloy system and is extended to a gener al form. The experiment shows that the possible band-edge fluctuation can b e grown-in at least between 3 to 170 meV with a single well-defined quasi-F ermi level. For different degrees of compositional fluctuation grown in the InGaN-quantum-well active layers in laser diodes. the differential gain an d compositional fluctuation show a strong correlation in full accordance wi th the theoretical model proposed here for a band-tail modified by In compo sitional fluctuation. Possible parameters, including differential gain, are discussed for optimization of laser performance.