Influence of stacking faults on the properties of GaN‐based UV light‐emitting diodes grown on non‐polar substrates

Abstract

We report on the reduction of defect densities in non-polar a-plane GaN films over r-plane sapphire achieved by epitaxial laterally overgrowth (ELOG) approach. A mask pattern was used to produce ELOG GaN with wing region width of about 30 µm. Based on transmission electron microscopy (TEM) results, the window regions have stacking faults density of ∼106 cm–1 and threading dislocation density of ∼1010 cm–2. Both ELOG Ga-face and N-face wing regions have stacking fault density of ∼105 cm–1, and dislocation density less than 108 cm–2. Cathodoluminescence studies reveal the difference in defect densities between N-faced and Ga-faced wings. GaN-based UV light-emitting diode formed on Ga-faced wing shows stronger quantum well emission and weaker parasitic emission than that formed on N-faced wing. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)