Blue light emitting diode fabricated on a‐plane GaN film over r‐sapphire substrate and on a‐plane bulk GaN substrate

We studied the growth technique for the dislocation reduction in a‐plane GaN grown by metal organic chemical vapour deposition (MOCVD) using AlInN buffer layer, high temperature atomic layer epitaxy, and trenched r‐sapphire technique. By using these techniques, the crystal quality was much improved. We also fabricated blue light emitting diodes (LEDs) on a‐plane GaN film over r‐sapphire substrate and on a‐plane bulk GaN substrate. The electroluminescence (EL) characteristics of the LED samples were examined, and we found that the EL near field pattern from homo‐epitaxially grown a‐GaN based LED was spatially uniform, although the pattern from the LED on r‐sapphire substrate was not uniform. The output power at the wavelength of 430nm was 0.72mW at the 20mA injection current for the sample on a‐plane bulk GaN. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)