The mechanism of Li, N dual-acceptor co-doped p-type ZnO

The formation of single defects and defect complexes are investigated in Li, N co-doped ZnO by the first-principles plane wave method with projector augmented wave (PAW) pseudo-potential technology. We find that: (i) p-type conductivity could be achieved in single Li doped ZnO under an O-rich condition, since the formation energy of Li-Zn acceptor is much lower than the interstitial Li-i; (ii) the dual-acceptor complex Li-Zn-N-O is unlikely to form, and the good p-type conductivity is mainly attributed to the Li-Zn acceptor, even in Li, N co-doped ZnO; (iii) the additional introduction of N may help compensate the single Li-i donor defects under certain growth conditions, but its role in the p-type conductivity in ZnO remains to be clarified.