| With wide-band-gap semiconductor and a large excitation binding energy at room temperature, wurtzite-structured ZnO is a perfect performance semiconducter material for optoelectronic devices. In the past decade, ZnO has aroused a lot of research attentions in many domains, such as physics, chemistry, material, and electronic. Recently, using the controlling technique, 3d transition-metal ions were doped in ZnO film to make the diluted magnetic semiconductors(DMS). Presently, DMS received increasing interests in the world. However, in this field the study is just in the initial stage in China. To aim directly at the condition which most reports studied the ferromagnetic of DMS, we discussed that the structure, morphology, photoluminescence, and surface states of ZnO:V and ZnO:Co films. For the development and application of the ZnO (DMS), these studies are interesting.In this work, the sturcture, properties, and application were reviewed. At the same time, we introduced the methods of fabrication and measurement.In this work, we prepared ZnO/Si(100) by sol-gel process and investigated the influence of the new method (including the temperature of the annealing and the time of the before-annealing) on the structure, morphology, photoluminescence, and surface states. The suitable conditions of the experiment were obtained. These results offered the proofs for fabrication ZnO:V and ZnO:Co film.Through XRD, AFM, and PL measurements, we studied the influence of the temperature and the atmosphere of annealing on the PL of the ZnO:V film. It can be discovered that after doped 1% V, the wurtzite-structure of ZnO was not changed and the crystallite sizes in the V-doped ZnO films were more little than that in the undoped ZnO films. After the PL spectra of unannealing and annealing in air/oxygen at various temperatures were investigated, it can be concluded that the the UV emission peak was evidently enhanced while the visible emission band was weakened correspondingly after the V-doping in ZnO films annealed at 800oC in oxygen. That is, V doping can suppress defects and thus result in high UV emission efficiency. Additionally, the ZnO films doped with 1%, 5%, 10%, 20%, 30%, 40%, 50% vanadium were prepared and studied respectively. As the concentration of the vanadium increases, the intensities of the UV peaks and visible bands were enhanced previously. As the concentration reached to 5%, the intensities of the UV and the visible emission peaks were highest. In this work, the ZnO films doped with 1%, 3%, 5%, 10%, 15% cobalt by sol-gel were prepared and studied respectively. As the concentration of the cobalt increases, the crystallite sizes in the Co-doped ZnO films were decreased. The band-gap became narrow and the absorption edges were red-shifts. Such shifts were usually attributed to cobalt doping. It implied that when ZnO was doped with Co element, the electrons supplied by Co locating the lowest states in the band-gap, resulting in widen the conduction band and thus induced red-shifts of the absorption edges. XPS spectra indicated that with the consentration of Co increase, the valence states of Co element were increasing too. When the Co concentrations were≤5%, 10%, and 15%, the valence states of Co were +2, (+2～+3), and +3 respectively. The involvement of the lattice O and the absorption O were obtained by Gauss curve analysis. The results also indentified that the valence states of Co element were increased.In this work, the influences of ZnO films doping V or Co on the structure, morphology, photoluminescence, surface states were investigated deeply. The results offered some experiment proofs for the application of ZnO film on optoelectronic and DMS. |
PDF Full Text Request