The reduction of defect densities in non-polar a-plane GaN films over r-plane sapphire, achieved by using the epitaxial laterally overgrowth approach, was studied. A mask pattern was used to produce epitaxial laterally overgrown GaN with a wing region width of about 30µm. On the basis of transmission electron microscopy results, the window regions had stacking-fault densities of about 106/cm and a threading dislocation density of about 1010/cm2. Both epitaxial laterally overgrowth Ga-face and N-face wing regions had a stacking-fault density of about 105/cm, and a dislocation density of less than 108/cm2. Cathodoluminescence studies revealed a difference in defect densities between N-faced and Ga-faced wings.

Influence of Stacking Faults on the Properties of GaN-Based UV Light-Emitting Diodes Grown on Non-Polar Substrates. C.Q.Chen, V.Adivarahan, M.Shatalov, M.E.Gaevski, E.Kuokstis, J.W.Yang, H.P.Maruska, Z.Gong, M.A.Khan, R.Liu, A.Bell, F.A.Ponce: Physica Status Solidi C, 2005, 2[7], 2732-5