Annealing in tellurium-nitrogen co-doped ZnO films: The roles of intrinsic zinc defects

Abstract

In this article, the authors have conducted an extensive investigation on the roles of intrinsic zinc defects by annealing of a batch of Te-N co-doped ZnO films. The formation and annihilation of Zn interstitial (Zni) clusters have been found in samples with different annealing temperatures. Electrical and Raman measurements have shown that the Zni clusters are a significant compensation source to holes, and the Te co-doping has a notable effect on suppressing the Zni clusters. Meanwhile, shallow acceptors have been identified in photoluminescence spectra. The NO-Zn-Te complex, zinc vacancy (VZn)-NO complex, and VZn clusters are thought to be the candidates as the shallow acceptors. The evolution of shallow acceptors upon annealing temperature have been also studied. The clustering of VZn at high annealing temperature is proposed to be a possible candidate as a stable acceptor in ZnO.