The evolution of ZnO nanorods by metal-organic chemical vapor deposition onto sapphire substrates, and an investigation of their microstructure, was reported. Well-aligned ZnO nanorods with a high aspect ratio were grown onto an interfacial layer with several types of defect at a lower reactor pressure. Planar defects such as stacking mismatch boundaries and inversion domain boundaries were formed in the interfacial layer during the coalescence of the islands, and finally constituted the side facets of the nanorods. Based upon the microstructural changes and origin of the defects in the interfacial layers, a model was proposed in order to explain the growth evolution of ZnO nanorods on sapphire substrates.

Defects in Interfacial Layers and Their Role in the Growth of ZnO Nanorods by Metallorganic Chemical Vapor Deposition. Park, D.J., Lee, J.Y., Kim, D.C., Mohanta, S.K., Cho, H.K.: Applied Physics Letters, 2007, 91[14], 143115