| As one important component in semiconductor family, zinc-based semiconductor materials (such as ZnO, ZnS and ZnFe2O4 and so on) have exhibited specially outstanding optical, electronic and magnetic properties, which have promising applications in the fields of optical electronic devices, spin electronic devices and so on. It is well known that doping is an effective way to improve the physical and chemical properties of materials and enhance the performance of devices. In the aspect of magnetic properties of zinc-based semiconductor materials: Zinc-based semiconductor materials normally do not exhibit magnetism. Once transition metal is doped into them, the weak ferromagnetic properties will appear. They are the typical diluted magnetic semiconductors. So far, almost all the transition-metal-doped ZnO films are deposited on the flat substrates. However, during the growing process of ZnO films, the stress is inevitably formed due to the lattice mismatch and thermal expansion coefficient difference between the substrates and films, which will strongly influence their structures and properties. Unfortunately, few works have been reported about the relationship between the stress and the magnetic properties of diluted magnetic semiconductors. The transition-metal-doped ZnO films grown on the polystyrene particles array substrates can decrease the lattice mismatch. In addition, two elements codoping ZnO can enhance the carrier concentration of ZnO diluted magnetic semiconductors. Thus, in one part of this thesis, we deposit Cu, Co codoped ZnO thin films on the polystyrene particles array with different size by the magnetron sputtering technique, and try to investigate the effects of structure, stress, substrate curvature on the magnetic properties of ZnO diluted magnetic semiconductors. In the aspect of optical properties of zinc-based semiconductor materials: The essential condition to fabricated ZnO based LEDs is realizing three primary color emission. Although rare-earth doping is an effective way to introduce single primary color emission in ZnO, the mechanism of rare-earth ion emission is not clear. In addition, few work reports on the rare-earth-doped ZnO with the special morphology, especially for the ultra-thin graphene-like nanosheets. The energy band variation caused by the large specific surface area is quite beneficial for revealing the native luminescence mechanism of rare-earth in ZnO host. Therefore, in another part of this thesis, we choose Eu and Y as the dopants and synthesize the rare-earth-doped ZnO nanomaterials. Especially, we obtain the ZnO: Eu3+ ultra-thin graphene-like nanosheets, and reveal the luminescence mechanism of Eu ions. The obtained results for this thesis are described as follows:To decrease the lattice mismatch between ZnO diluted magnetic semiconductor films and substrates, we prepared Cu, Co codoped ZnO thin films on polystyrene particles array substrates by magnetron sputtering methods. All observed peaks can be indexed to the pure hexagonal wurtzite structure. No diffraction peaks corresponding to metallic Cu, Co or other phases are found. The type of the stress in Cu, Co codoped ZnO thin films on polystyrene particles array is biaxial compressive stress. Optical absorption spectra showed the absorption edge of our samples displayed blueshift with decreasing substrate curvature. The visible emission is defect-related for all samples, and their intensities obviously increase with decreasing the curvature. All the samples are ferromagnetic at room temperature, which are attributed to the 3d energy level splitting of Cu2+ ions. The study is very important to reveal the magnetic origin of diluted magnetic semiconductor. It provide the theoretical and experimental support not only for the development of the semiconductor spintronic device such as spin field effect transistor, spin light-emitting diode and so on, but also the integration of current separated information storage, disposal and display.To enhance the carrier concentration of ZnO diluted magnetic semiconductors, the Cu, Co and Cu, Al codoped ZnO nanoparticles were synthesized by sol-gel method. Zn0.9gCu0.02O and Zn0.95Cu0.02Co0.03O are pure hexagonal wurtzite structure. With the doping of Co ions, the UV emission peaks are restrained and the intensities of the visible light emission peaks increase. Zn0.9gCu0.02O and Zn0.95Cu0.02Co0.03O are ferromagnetic at room temperature. The ferromagnetism is originated from the increase of the defects when Co and Cu ions are embedded in the lattice of ZnO. The saturation magnetization increases when doping Co ions. With the increase of annealing temperature, the intensities of visible light emission peaks increase, the peak displays redshift and the saturation magnetization obviously increases. Compared with the samples sintering in the air, the crystallinity, the oxygen defects concentration and saturation magnetization of Zn0.97Cu0.02Al0.01O increase. These results testify that the control of the carrier concentration and magnetic ions concentration can improve the optical and magnetic properties of diluted magnetic semiconductors, which will provide theoretical and experimental foundation for the application of diluted magnetic semiconductor in the spintronic device field.To realize the single primary color emission in ZnO nanostructures, the graphene-like ZnO:Eu3+ nanosheets are synthesized successfully by a simple hydrothermal method. Due to the large surface-to-volume ratios, the graphene-like ZnO and ZnO:Eu3+ nanosheets exhibit the strong surface band bending and result in a redshift for their ultraviolet emission. With the increase of Eu3+ doping concentration, the intensity of the red emission at 613 nm originated from 5D0-7F2 of Eu3+ becomes stronger gradually. The excitation power-dependent PL spectra testify the existence of surface band bending in grapheme-like nanosheets and ZnO host resonantly transfer their energy to Eu3+ ions via oxygen defects as energy storage center. Although we did not observe the characteristic emission peak from Y3+ in ZnO:Y3+ nanoparitcles, the Y3+ doping prompt the redistribution of oxygen vacancy and oxygen intersitials, which results in that the peak with maximum intensity in deep-level emission band is gradually tuned from 539 nm to 598 nm. These results not only provide the candidate for the ZnO based white LED and flat display, but also build theoretical and experimental foundation for further improve the optical properties of rare-doped ZnO nanostructures.The ZnFe2O4 semiconductors are usually superparamagnetic. To introduce ferromagnetism in them, we doped Eu3+ and Nd3+ into the ZnFe2O4 and prepared the ZnFe1-xRExO4 (RE=Eu, Nd) nanoparticles by the sol-gel method. With the increase of Eu3+doping concentration, both the coercivity and saturation magnetization increase. With increasing the annealing temperature, the coercivity of ZnFe1.97Eu0.03O4 increases. Since the larger spin and orbit magnetic moment of Nd3+, the coercivity and saturation magnetization of ZnFe1.97Nd0.03O are larger than that of ZnFe1.97Eu0.03O4. These results provide experimental foundation for further adjust the magnetic properties of ZnFe2O4.This thesis not only provides the optimized preparation technique for the doping Zn-based semiconductor materials, but also improves their optical and magnetic properties, which provide the theoretical and experimental support for their application in white LED and spintronic devices.
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