Single quantum-well structure blue-light emitting InGaN diodes were grown onto epitaxially laterally overgrown GaN or sapphire substrates. The emission spectra exhibited a similar blue-shift, with increasing forward current, for both light-emitting diodes. The output power of both diodes was almost the same, but the one on sapphire exhibited a considerable amount of leakage current in comparison with the other. It was concluded that the In composition fluctuation was not caused by dislocations, that dislocations did not act as non-radiative recombination centers in InGaN, and that dislocations formed the leakage-current pathways in InGaN.

InGaN-Based Blue Light-Emitting Diodes Grown on Epitaxially Laterally Overgrown GaN Substrates. T.Mukai, K.Takekawa, S.Nakamura: Japanese Journal of Applied Physics - 2, 1998, 37[7B], L839-41