The Study On Structure And Properties Of Cu-ZnO Films By RF-Magnetron Sputtering

ZnO films, a directly wide band gap semiconductor, have been actively studied because of its potential applications. It can be used in solar cells, piezoelectric devices, optoelectric devices, transparent conducting electrodes and gas sensors. The characteristics of ZnO films can be modulated by the appropriate dopant. Specially, the studies for diluted magnetic semiconductors (DMSs) have now attracted much attention of many researchers. It has been found that the diluted magnetic semiconductors formed by replacing the cations of II-VI, IV-VI or III-V nonmagnetic semiconductors by transition Fe, Mn, Co and Cr exhibit a number of unique magnetic, magneto-optical, and magnetotransport properties, applicable for magnetoelectronic and spintronic devices. Recently, many research groups has done great efforts on the study for ZnO based DMSs and gotten a series of research results. But disputes appeared in the explanation of the origin of magnetism. So, further experimental and theoretical investigations are needed to address this issue.To research the effects of Cu dopant on the structure,photoluminescence properties (PL) and magnetron properties of ZnO films, in this paper, we prepared Cu-doped ZnO films by radio frequency (RF) magnetron sputtering and studied the characteristics,photoluminescence properties and magnetron properties by XRD, XPS, SEM, SQUID methods.1. Cu_xZn_1-xO(x=0, 0.038,0.073, 0.145, 0.321) films were deposited on oriented p-type Si (111) substrates by reactive RF magnetron sputtering. XPS and XRD results indicate that Cu²⁺ ions have substituted for Zn²⁺ successfully, and the films were well oriented to the c axis (002). SOUID results show that the Cu doped ZnO films were ferromagnetic and have a T_c higher than room temperature, and the origin of the ferromagnetic of the films were explained by the BMPs modle because of a larger numbers of O disfigurement exist in the Cu doped films.2. Cu_xZn_1-xO(x=0, 0.038, 0.073, 0.145, 0.321) films were also deposited on quartz glasses, the optical test shows that the optical band gap E_g were decreased within the increase of Cu doped in ZnO, so one can modulate the E_g by controlling the concentration of the Cu. We also find that the transmission rate were decreased rapidly when the Cu concentration was increase.