Probing deactivations in Nitrogen doped ZnO by vibrational signatures: A first principles study

Based on first principles calculations, we investigate two probable types of deactivation mechanisms that hinder current efforts of doping ZnO p-type. (i) Passivation by Hydrogen. H prefers to bind with No at the anti-bonding site and form NO-H complexes with a binding energy of about 1 eV. (ii) Passivation by the formation of substitutional diatomic molecules (SDM). Carbon impurities and excess N strongly prefer to passivate No and form low-energy SDM on the Oxygen site, (NC)(O) or (N-2)(O), both of which are donors with several-eV binding energies. Our calculated vibrational frequencies of No-H complexes and SDMs are consistent with the frequencies recently observed by IR measurement on N-doped ZnO, which is not p-type. (c) 2005 Elsevier B.V. All rights reserved.