Simulating random alloy effects in III-nitride light emitting diodes

Statistical fluctuations in the alloy composition on the atomic scale can have important effects on electronic and optical properties of bulk materials and devices. In particular, carrier localization induced by alloy disorder has been a much discussed topic during the last decade with regard to III-nitride light emitting diodes (LEDs). Much experimental and theoretical work has been dedicated to the study of the effects of alloy disorder on carrier localization and finally on the efficiency and transport properties in such devices. Modeling approaches range from empirical analytical models down to atomistic ab initio ones, each with its advantages and disadvantages. In this tutorial, we discuss the simulation of alloy fluctuations in nitride quantum well LEDs by combining continuum device models and an atomistic empirical tight binding model, which provides a suitable compromise between atomic precision and computational effort.