| ZnO is a direct band gap semiconductor, which has a band gap of 3.37eV at room temperature and the binding energy of exciton up to 60 meV. Besides. ZnO is abundant in the natural world. All the advantages mentioned above make ZnO one of the most potential materials used in short wavelength electronic devices. However, even though the ZnO based photoelectric device has been investigated for many years, the practical use of ZnO based device has not yet make a breakthrough. At present, the preparation of p-type ZnO film with high crystalline quality, low resistivity, stable and controllable hole concentration has been the bottleneck of ZnO based devices. In resent years, the investigation of stable and reproducible p-type ZnO film has been the focus of international research and also the primary problem. In this thesis, systematical investigations on the preparation of p-type ZnO film is carried out by using magnetron sputtering and annealing techniques. And the details are as follows:1. By using multi-target co-sputtering method, Sb-doped ZnO films were fabricated on n-type Si (100) substrate, with the mixture of Ar and O2 as the working gas and high-purity Zn (99.999%) and Sb (99.99%) as the targets. By fixing the sputtering power on Zn target and changing the sputtering power on Sb target, undoped and Sb-doped ZnO with wurtzite structure and (002) preferred orientation were grown at 550℃. and then films were annealed in vacuum at 750℃for 30 minutes. It is deduced from XRD and XPS measurement that the Sb in the as-grown ZnO:Sb has high oxidation state and dopes in the form of oxygen-rich Sb-O clusters. which results in a large inner stress and a great increase of the c-axis lattice constant. After annealing at 750℃under vacuum, the c-axis lattice constant of the ZnO:Sb decreases sharply to near the value of ZnO bulk, the electrical properties change from n-type to p-type and the PL intensity ratio of the visible to ultraviolet emission band goes down greatly, as the Sb content increases from 0 to 2.1 at.%. EDS and XRD measurements indicate that some of Sb dopants escape from the ZnO:Sb films and the oxygen-rich Sb-O clusters vanished after the annealing process. The effect of the change in Sb doping behavior on crystal structure, conductivity and PL is discussed in detail.2. By using RF magnetron sputtering method, Ag doped ZnO films were fabricated on quartz with the mixture of Ar and 02 as working gas, and the substrate temperature were 200℃,350℃and 500℃, respectively. And then the as-grown films were annealed in vacuum at 600℃. EDS and XRD measurements show that the Ag content decreases with the increase of substrate temperature. For the as-grown film deposited at 200℃, the Ag content is the largest, but the Ag dopant incorporated in ZnO is least; while after the annealing process, all of Ag dopant segregates from ZnO. For the as-grown films deposited at 350℃and 500℃, there is only wurtzite phase of ZnO; but after the annealing process, for film deposited at 350℃all of Ag dopant segregates from ZnO, and for film deposited at 500℃there is still some Ag dopant that incorporated in ZnO. By Gaussian fitting of the ZnO (002) diffraction peaks, we gain the full width of half maximum of them and calculated the grain sizes of all samples. By analyzing the dependency relationship between the grain sizes and the solubility of Ag in ZnO, it is deduced that a larger grain size in the as-grown films facilitates improving the solubility of Ag in ZnO.By analyzing the absorption and photoluminescence spectra of the Ag-doped films, the effects of Ag metal that segregated from ZnO on the optical properties of the films were also studied. The low-temperature photoluminescence spectrum of the annealed film which deposited at 500℃shows that acceptor about AgZn is formed3. By using RF magnetron sputtering method, Ag-S co-doped ZnO films were fabricated on quartz with the substrate temperature of 200℃.350℃and 500℃. And then the as-grown films were annealed in vacuum at 600℃for 15 minutes. The XRD measurements show that the crystal quality of the films is improved with the increase of substrate temperature, which is contrary to the Ag mono-doped ZnO films. XRD, EDS and Hall measurements suggest that in the film grown at higher substrate temperature, there is less S dopant, Ag dopant is easer to separate out and the electron density is higher. By comparison of the low-temperature photoluminescence spectra of the annealed films grown at 200℃and 350℃, it is found that there are A0X emission peak about AgZn and AgZn-nSO in spectrum of the film grown at 200℃, while there is no emission peak about Ag dopant in spectrum of the film grown at 350℃. Above analyzation implies that by using a lower substrate temperature, the solubility limits of Ag and S dopants in ZnO could be improved, and the the p type ZnO film is more likely fabricated.Based on the above experiment condition, the substrate temperature is decreased to room temperature and both quartz and Si with high resistance were used as the substrates. The as-grown films were annealed in vacuum at 450℃and 600℃, respectively. XRD and Hall measurements show that the film deposited on Si substrate and annealed at 450℃possesses the best crystal quality and shows p-type conductivity, and a pn homojunction was fabricated to prove its p-type conductivity. EDS measurements suggest that the S content in the film is related to the substrate, while the Ag content is related to the annealing temperature. Both Ag and S contents in the p-type film are larger then that of other films. And XPS measurement show that there are Ag-S bonds in the p-type film.
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