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HL: Halbleiterphysik

HL 36: Theorie

HL 36.9: Talk

Thursday, March 26, 1998, 18:30–18:45, H15

Ab initio study of native defects in ZnO — •Xiliang Nie and Stefan Bl"ugel — Institut f"ur Festk"orperforschung, Forschungszentrum J"ulich, 52425 J"ulich

We present an ab initio LAPW study on the basis of the density functional theory in the local density approximation to native defect structures of ZnO, which play the basic physical roles for nonlinear ZnO resistors. We investigated 4 different defects: O-vacancy, Zn-vacancy, O-interstitial and Zn-interstitial. The results show that in both cases two type of defects lead to a donor and an acceptor state within the band gap: (i) an O vacancy or a Zn interstitial form a donor state, and (ii) an O interstitial or a Zn vacancy form an acceptor state. These results are in good agreement with experimental findings. This means defects, which exist at grain-boundary like interfaces, are possible to generate a band bending for pure ZnO varistors.