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 systems that have a tailorable band-tail. The model is constructed from experimentally derived data on the InGaN alloy system and is extended to a general form. The experiment shows that the possible band-edge fluctuation can be grown-in at least between 3 to 170 meV with a single well-defined quasi-Fermi level. For different degrees of compositional fluctuation grown in the InGaN-quantum-well active layers in laser diodes, the differential gain and compositional fluctuation show a strong correlation in full accordance with the theoretical model proposed here for a band-tail modified by In compositional fluctuation. Possible parameters, including differential gain, are discussed for optimization of laser performance.