I did not get clear reply from semiconductor experts. But from my knowledge,

(1)The n-conductivity of undoped ZnO comes from O vacancies, Zn interstitials and H impurities.

(2)These defects form new energy bands, which have higher energy than O2p.

(3)So the UCSB’s work of comparing O2p and N2p is not convincing to their conclusion that N atoms doped in ZnO are deep acceptors.

(4)But their suggestion of doping F to prepare p-ZnO sounds reasonable, because F might be able to withdraw electrons in the energy bands contributed by the defects, and change n- to p-conductivity.

Quantum computation concerning the defects consumes much time, but we can expect some comments on this UCSB’s paper.