PreParation、Characterization And In Situ High-temperature Study Of ZnO Thin Films And Research Of Capillary Focusing

ZnO is a direct wide band gap compound semiconductor (Eg-3.3eV at300K), it has large exciton binding energy about60meV, theoretically, it can realize stimulated ultraviolet emission at room temperature. Compared with GaN, the ZnO films have attracted more and more attention. ZnO can be applied in a wide range of areas, for instance, transparency electrode、piezoresistance、cell battery、surface acoustic wave device、gas sensor and light-emitting diode. However, the application of ZnO is hindered mainly due to the difficulty in achieving reliable and reproducible p-type ZnO, So it is very important to prepare high quality ZnO thin film.In this thesis, we report that ZnO thin films on different substrates of Si、SiC and Al2O3are prepared by pulsed laser deposition(PLD) and molecular beam epitaxy (MBE). Furthermore X-ray diffraction(XRD)、grazing incidence X-ray diffraction (GID)、X-Ray diffraction rocking curve、photo luminance(PL)spectra、In situ high temperature X-ray diffraction and some normal analysis methods were employed to investigate the influence of different growth conditions on structure, optical and the interface information of ZnO thin films. Influence of Mn-doped on the structure and optical properties of ZnO thin films were also investigated. The major results are listed as the following:1. The epitaxial growth of ZnO thin films on Al2O3substrate and investigation of their structure and optical propertiesZnO thin films were entirely fabricated by pulsed laser deposition (PLD) on Al2O3substrate. The effects of substrate temperature on the structure, lattice relaxation and the interface information of ZnO thin films were investigated. The results show that:the formation of ZnO films with a preferred c-axis orientation, an optimal crystallized ZnO thin film was observed at the substrate temperature of600℃. Then some of the samples were treated with different annealing ambience(nitrogen、air and oxygen) conditions. After annealing processing, at the same annealing temperature, the film annealed under oxygen ambience shows better qualities. PL spectrum is strongly connected with its crystallization condition, the better of crystallization condition, the stronger of UV eradiation. Oxygen antisite defects(OZn) in ZnO films, which enhance the green emission in photoluminescence.2. Influence of substrates on the structure and optical properties of ZnO thin films ZnO thin films were entirely fabricated by PLD on Al2O3and Si substrate. XRD results show that ZnO thin films on Al2O3substrate have better crystalline quality. PL results show that ZnO thin films on Si substrate have more defects, which results in a green-emitting. ZnO thin films were prepared on the ZnO single crystal substrate by plasma-assisted molecular beam epitaxy (P-MBE) method. XRTXGID and Phi-scan XRD were employed to investigate the structure properties of ZnO thin film. The results show that single crystal ZnO thin film is prepared successfully, The results of GID indicate that the crystal relaxation along the a-axis in ZnO thin film is not uniform.3. Influence of Mn-doped on the structure and optical properties of ZnO thin filmsZn1-xMnxO thin films were successfully grown on Si substrates by PLD. The crystalline quality of Mn doped ZnO thin films was worse than that of undoped sample; The results indicate that Zn0.9Mn0.1O alloy forms after Mn doping in ZnO. Mn atoms enter into the ZnO crystal lattice and substitute Zn atoms with Mn2+state. As a result, the band gap of Zn0.9Mn0.1O increases, which is associated with the UV emission blue-shift. Furthermore, after Mn doping, Oxygen vacancy(Vo)increases, showing the increasing of green emission of the film samples.4. In situ high-temperature XRD studies of ZnO thin filmsZnO thin films were entirely fabricated by pulsed laser deposition (PLD) on different substrate. In situ high-temperature XRD studies of ZnO thin film show that the crystallite size increases with increasing temperature and the lattice parameters show linear variation in their values with increasing temperature. High-temperature XRD also confirms that the ZnO thin film is stable not only at room temperature but also at high temperature (900℃).In situ high-temperature XRD studies of Zn0.9Mn0.1O/Si thin film show that the crystallite size decreased first, then increased with increasing temperature; the crystal quality of Zn0.9Mn0.1O/Si films change from worse to better with increasing temperature; the lattice parameters show linear increase in their values with increasing temperature. High-temperature XRD also confirms that the Zn0.9Mn0.1O thin film is stable not only at room temperature but as well at high temperature (900℃).5. Study on Single-bounced Capillary Focus Based on NSRL X-ray Diffraction and Scattering StationThe X-ray Diffraction and Scattering beamline is focused by Single-Bounced capillary. Beam diameter of125μm was obtained at the focal point, and beam intensity of two times was reached. To test the capillary in the real crystallorgraphy experiments, diffraction images for lysozyme crystal with and without capillary were collected by mar345Image Hate Detector. The results show that exposure time can be shortened by half with the capillary and the efficiency of the collection images has been improved.