Characterization of semipolar (11$ \bar 2 $2) GaN on c ‐plane sapphire sidewall of patterned r ‐plane sapphire substrate without SiO2 mask

Abstract

AbstractWe succeeded in growing a semipolar (11$ \bar 2 $2) GaN layer on a patterned r ‐plane sapphire substrate (r ‐PSS) without a SiO2 mask by metal‐organic vapor phase epitaxy. Under various growth conditions, the semipolar (11$ \bar 2 $2) GaN layer was only grown on the c ‐plane‐like sapphire sidewall of the r ‐PSS without a SiO2 mask which shows r ‐PSS is useful to obtain (11$ \bar 2 $2) GaN. The specific characteristics of the (11$ \bar 2 $2) GaN on the r ‐PSS were investigated by X‐ray diffraction measurement, atomic force microscopy (AFM), transmission electron microscopy and photoluminescence. The full width at half maximum of X‐ray rocking curve of coalesced sample were 722 and 319 arcsec along the azimuths parallel and perpendicular to the c ‐direction, respectively. The macrosteps were observed by AFM observation. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)