Käbisch, S.; Gluba, M.A.; Klimm, C.; Krause, S.; Koch, N.; Nickel, N.H.: Polarity driven morphology of zinc oxide nanostructures. Applied Physics Letters 103 (2013), p. 103106/1-4
10.1063/1.4820410

Abstract:
Catalyst-free ZnO nanostructures were grown by pulsed-laser deposition on c-oriented sapphire. The nanostructure morphology can be controlled by introducing a nucleation layer. Depending on the doping concentration in the nucleation layer two distinct types of nanostructures are observed. On intrinsic nucleation layers nanowires form, while Al-doping results in a honeycomb network of nanoscale walls. From scanning-electron microscopy and X-ray photoelectron spectroscopy a correlation between nanostructure morphology and the polarity of the nucleation layers is derived.