Optical and Electrical Properties of p-type ZnO∶N Films Grown by N-plasma Assisted Pulsed Laser Deposition

Nitrogen-doped ZnO(ZnO∶N) films were grown by N-plasma assisted pulsed laser deposition.The p-type conductivities were achieved by post low-temperature rapid thermal annealing(RTA).The N chemical states,optical and electrical properties of ZnO∶N films were systematically studied by X-ray photoelectron spectroscopy(XPS),photoluminescence(PL) and Hall measurements.The results revealed that the obtained p-type ZnO∶N films are highly compensated semiconductor,and the RTA process can activate more N acceptors and reduce the self-compensation of intrinsic donor defects.Three N acceptor-related emissions were observed in low-temperature PL spectra.The ionization energy of N acceptor was determined as about 128 meV from free-electron-to-acceptor(FA) transition.Interestingly,donor-acceptor pair(DAP) emission showed a slight redshift with increasing annealing temperature.This phenomenon was understood in terms of a potential fluctuation model.