Improved Crystal Quality of (11(2)over-bar2) Semi-Polar GaN Grown on A Nanorod Template

(11 (2) over bar2) semi-polar GaN with significantly improved crystal quality has been achieved by means of overgrowth on a (11 (2) over bar2) semi-polar nanorod template. The nanorod template was fabricated on a standard (11 (2) over bar2) semi-polar GaN layer on m-plane sapphire using a self-organized nickel nano-mask technique. In comparison with any conventional overgrowth technique, the nano-mask approach has demonstrated a very quick coalescence with a thickness of less than 1 mu m. X-ray rocking curve measurements as a function of azimuth angle has shown a massive reduction in linewidth for our overgrown GaN. Transmission electron microscope measurements have confirmed a significant reduction in the dislocation density. Dramatic improvement in optical properties has been exhibited by photoluminescence (PL) measurements performed at room temperature, showing that the PL intensity from the band edge emission is 30 times higher than that of the standard semi-polar GaN on sapphire. (C) 2013 The Japan Society of Applied Physics