Observation of unintentionally incorporated nitrogen-related complexes in ZnO and GaN nanowires.

We report the observation of unintentionally incorporated nitrogen-related complexes in ZnO and GaN nanowires grown by the catalytic vapor-phase transport method. In particular, our experimental findings from Raman scattering spectroscopy and mass-selected time-of-flight particle emission measurements suggest the presence of interstitial nitrogen molecules that are formed during the nanowire growth. These results may be relevant for many nanowire systems, emphasizing the necessity of more studies on unintentional impurity incorporations in these nanomaterials.