Doping by Large-Size-Mismatched Impurities: The Microscopic Origin of Arsenic- or Antimony-Doped p -Type Zinc Oxide

National Renewable Energy Laboratory, Golden, Colorado 80401, USA.
Physical Review Letters (Impact Factor: 7.51). 05/2004; 92(15):155504. DOI: 10.1103/PhysRevLett.92.155504
Source: PubMed


Based on first-principles calculations, a model for large-size-mismatched group-V dopants in ZnO is proposed. The dopants do not occupy the O sites as is widely perceived, but rather the Zn sites: each forms a complex with two spontaneously induced Zn vacancies in a process that involves fivefold As coordination. Moreover, an As(Zn)-2V(Zn) complex may have lower formation energy than any of the parent defects. Our model agrees with the recent observations that both As and Sb have low acceptor-ionization energies and that to obtain p-type ZnO requires O-rich growth or annealing conditions.


Available from: Sukit Limpijumnong
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    • "who suggested that annealing at high temperature in O-rich atmosphere may result in breaking of the As–O bonds and formation of As Zn –2V Zn acceptor-like complexes [16] [18]. "
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    • "It is seen that the monodoped film (AlN ¼ 0%) showed p-conductivity with the hole concentration , $ 10 15 cm À 3 due to the diffusion of As atoms into ZnO. Here, the As sits on Zn site and thereby forms (As Zn À 2V Zn ) complexes which gives rise to p-conductivity [10]. Further, the hole concentration increases with the increase of AlN concentration (till 1 mol%) due to the incorporation of both N and As acceptors into ZnO. "
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    • "The finding that majority of the Asatom occupying the Zn site of the ZnO lattice was also compatible with the As Zn (V Zn ) 2 shallow acceptor model. The observed increase of the Zn-vacancy open volume also agreed with the theoretical prediction of the atomic relaxation and thus the increase of the relevant V Zn volume that would occur with the formation of the As Zn (V Zn ) 2 complex [25]. It is thus plausible to attribute the As Zn (V Zn ) 2 complex to the shallow acceptor responsible for the p-type conductivity observed in the present study. "
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