InGaN-Based Blue Light-Emitting Diodes Grown on Epitaxially Laterally Overgrown GaN Substrates

InGaN single-quantum-well-structure blue light-emitting diodes (LEDs) were grown on epitaxially laterally overgrown GaN (ELOG) and sapphire substrates. The emission spectra showed the similar blue shift with increasing forward currents for both LEDs. The output power of both LEDs was almost the same, as high as 6 mW at a current of 20 mA. The LED on sapphire had a considerable amount of leakage current in comparison with that on ELOG. These results indicate that the In composition fluctuation is not caused by dislocations, the dislocations do not act as nonradiative recombination centers in the InGaN, and the dislocations forms the leakage current pathway in InGaN.