Phase control of semi-polar (112¯2) and non-polar (112¯0) GaN on cone shaped r-plane patterned sapphire substrates

► Phase control of (112¯2) and (112¯0) GaN grown on r-plane CPSS is studied. ► Growth competition between (112¯2) and (112¯0) GaN is severely influenced by the nucleation temperature. ► Optimized completion of a-plane (112¯0) GaN enables a smooth surface on r-plane CPSS.