Growth of AlGaN containing nanometer scale compositional inhomogeneities for ultraviolet light emitters

Abstract

The incorporation of nanometer scale compositional inhomogeneities in AlGaN has a great promise for improving the performance of UV light emitting diodes based on these materials by suppressing nonradiative recombination associated with dislocations. In this article, the authors report on the growth and characterization of AlGaN containing nanometer scale compositional inhomogeneity (NCI-AlGaN) alloys deposited by plasma-assisted molecular beam epitaxy. Growth under N-limited and nearly stoichiometric growth is observed to enhance the photoluminescence intensity in AlGaN alloys by promoting the spontaneous formation of these NCI regions. This is attributed to the lower adatom mobility of group III and N species on the AlGaN layer surface under these conditions as well as the formation of beneficial surface faceting.