Self-catalyzed, vertically aligned GaN rod-structures by metal-organic vapor phase epitaxy

This paper will discuss the influence of parameters such as temperature, V/III ratio, atmosphere and pressure on the vertical growth of GaN rod-structures on sapphire by metalorganic vapor phase epitaxy. For all growth experiments a simple two step method is applied consisting of a nitridation step on the sapphire substrate and the growth of GaN. Vertically aligned rod-like structures were achieved with this mask-free and catalyst-free approach. The influence of the nitridation step on the formation process of the vertically rodstructures will be discussed. The results will give an insight into the formation of vertically aligned GaN structures which is an important step towards the understanding and control of self-assembled GaN rods and nanorods in metal-organic vapor phase epitaxy. (C) 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim