Wischmeier L, Voss T, Rückmann I, Gutowski J
Institute of Solid State Physics, University of Bremen, PO Box 330 440, D-28334 Bremen, Germany.
Nanotechnology. 2008 Apr 2;19(13):135705. doi: 10.1088/0957-4484/19/13/135705. Epub 2008 Feb 26.
We report on the investigation of correlated spectral properties of two different surface-related photoluminescence bands in ZnO nanowires. We show that the spectral position and the temperature-dependent intensity of the surface-related emission band A are directly correlated with the emission of the surface-exciton band SX. We measure the thermal activation energies of both emission bands and present time-resolved photoluminescence data to deduce the photoluminescence decay time of the A emission band. We propose a model to explain the experimental observations and assign the A emission band to excitons bound to structural defects in the surface layer of the nanowires.
