Zn interstitial related donors in ammonia-treated ZnO powders

ZnO powder heat treated in NH3 atmosphere was investigated by electron paramagnetic resonance, photoluminescence, and Raman spectroscopy. We find that the treatment creates Zn interstitials (Zn-i) and complexes of Zn interstitials and nitrogen atoms substituting oxygen (Zn-i-N-O). A correlation between the Zn-i and an exciton at 3.366 eV (I-3) can be stated by a comparison with the PL results; furthermore, the (Zn-i-N-O) complex seems to be related to a recombination at 3.193 eV.