Catalyst-free vapor-phase transport growth of vertically aligned ZnO nanorods on 6H-SiC and (11-20)Al2O3

ZnO nanostructures are expected to pave the way for many interesting applications in optoelectronics, spin electronics gas sensor technology and biomedicine. Fabrication methods, especially for nanorods have been based mostly on catalyst-assisted growth methods that employ metal-organic sources and other contaminating agents like graphite to grow ZnO nanorods at relatively high temperatures. We report on the growth of ZnO nanorods on 6H-SiC and (11-20)Al2O3 using purely elemental sources, without catalysis and at relatively low temperatures and growth pressure in a specially designed vapor-phase transport system. ZnO nanorods with widths of 80-900 nm and lengths of 4-12 mu m were obtained. Nanorod concentrations of up to 10(9) cm(-2) with homogenous luminescence and high purity were noted. (c) 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.