Characteristics of undoped and Sb-doped ZnO thin films prepared in different atmospheres by pulsed laser deposition

摘要

Undoped and 0.56 at.% Sb-doped ZnO thin films were prepared by pulsed laser deposition (PLD) under vacuum and an oxygen pressure of 0.2 Pa with sintered ceramic as targets. The effects of Sb doping and deposition atmosphere on structure and optical-electrical properties of the films were studied by X-ray diffraction (XRD), scanning probe microscopy (SPM), Hall Effect measurement, transmittance spectra, and photoluminescence (PL) spectra. The results showed that undoped and Sb-doped films deposited under vacuum had better crystallinity, higher carrier concentration, lower bandgap (E_g), and single violet emission as compared with the films deposited in an oxygen pressure of 0.2 Pa. Compared with undoped ZnO film, Sb-doped ZnO film had higher carrier concentration and almost uniform E_g in both atmospheres, and it exhibited obviously improved crystallinity and green emission under an oxygen pressure of 0.2 Pa. The results implied that the deposition atmosphere strongly affected the growth kinetics of the films and intrinsic defect im the films, and Sb doping seemed also to affect the growth kinetics of the films under certain conditions and introduced Sb_Zn defects and possibly Sb_Zn-2V_Zn defects, thus the structure and optical-electrical properties of the films were modified by the deposition atmosphere and Sb doping.