Effect of alloy non-uniformity on optical properties of InGaN bulk and quantum wells

In this work we present a theoretical study of the effects of nanometer-scale non-uniformities in InGaN alloys on their optical properties. We show by empirical tight-binding calculations that, compared to a random alloy, deviations from uniformity lead to an increasing scattering of both the optical matrix elements and the emission energy. While the extracted B-parameter of radiative recombination appears to be relatively insensitive to small non-uniformities, at larger degree of In clustering we can demonstrate the transition to quantum dot like behaviour. Our results show that alloy non-uniformity allows to reproduce both the measured spectral width of electroluminescence spectra and temperature behaviour of the radiative recombination parameter.