Emission and recombination characteristics of Ga1-xInxN/GaN quantum well structures with nonradiative recombination suppression by V-shaped pits

We demonstrate quantitatively that the realization of high internal quantum efficiency of more than 70% at room temperature in GaInN/GaN quantum well structures is possible with potential barriers, which are caused by V-shaped pit formation around threading dislocations. Localization of charge carriers is present in the samples, but its contribution to room temperature quantum efficiency is negligible. The emission and recombination characteristics of GaInN/GaN quantum well structures with deep V-shaped pits are studied in detail. Due to narrower wells and smaller piezoelectric fields, the GaInN quantum wells on the facets of extended V-shaped pits emit several hundred meV higher in energy than the c-plane quantum wells. Because of the simultaneous growth, the emission energies of the c-plane and the V-shaped pit quantum wells are correlated. The relative intensity of both emissions depends on the ratio between the c-plane and the V-shaped pit surface area during GaInN quantum well growth. GaInN/GaN LED structures from different commercial sources feature V-shaped pits and their effects on the emission characteristics, too. Hence, a universal relevance of V-shaped pit potential barriers around dislocations in GaInN/GaN heterostructures for high internal quantum efficiency is suggested.