Local structure of luminescent InGaN alloys

Abstract

Comparative Ga and In K-edge extended x-ray absorption fine structure studies provide the first direct evidence of an inequality of mean In–Ga and Ga–In next-nearest neighbor separations in InGaN alloys. The degree of inequality increases with decreasing InN fraction x in the range accessible to extended x-ray absorption fine structure analysis of alloys (0.9<x<0.1). Its concurrence with an increase of luminescence efficiency in this composition range suggests that the breakdown of In∕Ga randomness in InGaN is correlated with efficient radiative recombination in blue-green light emitting devices.