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Valency Configuration of Transition Metal Impurities in ZnO

L. Petit·T. C. Schulthess·A. Svane·W. M. Temmerman·Z. Szotek·A. Janotti
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Abstract

We use the self-interaction corrected local spin-density approximation to investigate the ground state valency configuration of transition metal (TM = Mn, Co) impurities in n- and p-type ZnO. We find that in pure Zn1-xTMxO, the localized TM2+ configuration is energetically favored over the itinerant d-electron configuration of the local spin density (LSD) picture. Our calculations indicate furthermore that the (+/0) donor level is situated in the ZnO gap. Consequently, for n-type conditions, with the Fermi energy eF close to the conduction band minimum, TM remains in the 2+ charge state, while for p-type conditions, with eF close to the valence band maximum, the 3+ charge state is energetically preferred. In the latter scenario, modeled here by co-doping with N, the additional delocalized d-electron charge transfers into the entire states at the top of the valence band, and hole carriers will only exist, if the N concentration exceeds the TM impurity concentration.

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L. Petit, T. C. Schulthess, A. Svane, W. M. Temmerman, Z. Szotek, A. Janotti. 2006-06-15. Valency Configuration of Transition Metal Impurities in ZnO. https://doi.org/10.1007/s11664-006-0099-8

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