ZnO powder heat treated in $\mathrm{N}{\mathrm{H}}_3$ atmosphere was investigated by electron paramagnetic resonance, photoluminescence, and Raman spectroscopy. We find that the treatment creates Zn interstitials (${\mathrm{Zn}}_i$) and complexes of Zn interstitials and nitrogen atoms substituting oxygen $\left({\mathrm{Zn}}_i\text{−}{\mathrm{N}}_{\mathrm{O}}\right)$. A correlation between the ${\mathrm{Zn}}_i$ and an exciton at $3.366\mathrm{eV}$ $\left({\mathrm{I}}_3\right)$ can be stated by a comparison with the PL results; furthermore, the $\left({\mathrm{Zn}}_i\text{−}{\mathrm{N}}_{\mathrm{O}}\right)$ complex seems to be related to a recombination at $3.193\mathrm{eV}$.

• Received 5 June 2007

DOI:https://doi.org/10.1103/PhysRevB.76.195203