Low temperature cathodoluminescence and temperature dependent time-resolved photoluminescence were used to investigate the emission properties of ZnO nanowires grown by metal organic vapor phase epitaxy. Low-temperature cathodoluminescence images show that the emission process was more efficient in ZnO nanowires than in the underlying 2-dimensional layer. Temperature dependent photoluminescence spectra and decay time measurements give a detailed insight on the role of the donor bound exciton, the free exciton, and the non-radiative channels in the emission process. In particular, it was shown that up to room temperature, the escape toward non-radiative channels was limited because of the very low defect density in the ZnO nanowires.

Evidence for Low Density of Nonradiative Defects in ZnO Nanowires Grown by Metal Organic Vapor-Phase Epitaxy. I.C.Robin, B.Gauron, P.Ferret, C.Tavares, G.Feuillet, L.S.Dang, B.Gayral, J.M.Gérard: Applied Physics Letters, 2007, 91[14], 143120