Effect of intrinsic defects on p-type conductivityof ZnO:(In, N) thin films

Abstract

Indium and nitrogen co-doped ZnO thin films [ZnO: (In, N)] were prepared on quartz glass substrate by radio frequency magnetron sputtering combined with ion implantation technique. By optimizing the annealing temperature, a repeatable p-type ZnO:(In, N) thin film with the hole concentration about 1016 cm−3 was successfully achieved. Using the Hall effect measurements, the n→p→n electrical transition phenomenon of the films with annealing temperature was observed. Then the effects of doped impurities and intrinsic defects on the structure and p-type conductivity of the films were investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and photoluminescence (PL) spectroscopy. It was found that the difference of N-related acceptor defects concentration between p-type and n-type ZnO is not prominent. Nevertheless, the content of intrinsic zinc interstitial (Zni) donor defects in p-type ZnO were less than that of n-type one, the intrinsic oxygen interstitial (Oi) and zinc vacancy (VZn) acceptor defects were relatively abundant. The conclusion can be drawn that besides the N-related acceptor defects (NO, InZn-nNO), the intrinsic defects (VZn, Oi, Zni) in the film also play a crucial role in realizing the p-type conductivity. Therefore, how to control the intrinsic defects in ZnO is an important means to realize the p-type transition and to improve p-type conductivity stability of ZnO thin film.