Nominally undoped ZnO nanorods, grown by a chemical method, were post-treated to intentionally incorporate high concentrations of zinc vacancies and zinc interstitials and were studied with electron microscopy and low temperature photoluminescence spectroscopy. The Zni were related to the 3.405eV peak at 4.2K, verifying that Zni was a shallow donor lying 30meV below the conduction band minimum, while the acceptors VZn were related to the 3.308eV peak at 4.2K and have an activation energy of 123meV.

Zinc Vacancies and Interstitials in ZnO Nanorods. Boukos, N., Chandrinou, C., Travlos, A.: Thin Solid Films, 2012, 520[14], 4654–7