Theoretical study of defect signatures in III - V and II - VI semiconductors

Based on first principles calculations, we investigate two probable types of deactivation mechanisms that hinder current efforts ofdoping ZnO p-type. (i) Passivation by Hydrogen. H prefers to bind with NO at the anti-bonding site and form NO–H complexes with abinding energy of about 1 eV. (ii) Passivation by the formation of substitutional diatomic molecules (SDM). Carbon impurities andexcess N strongly prefer to passivate NO and form low-energy SDM on the Oxygen site, (NC)O or (N2)O, both of which are donors withseveral-eV binding energies. Our calculated vibrational frequencies of NO–H complexes and SDMs are consistent with the frequenciesrecently observed by IR measurement on N-doped ZnO, which is not p-type.r 2005 Elsevier B.V. All rights reserved. PACS: 61.72.Bb; 61.72.Vv; 63.20.Pw; 78.30.Fs