Zno Micro-tube Study Of Materials, Optical And Electrical Properties

Zinc oxide (ZnO) is an interesting wide band gap (3.3eV) semiconductor material with a binding energy of 60 meV. It makes more attention to the ultraviolet optoelectronic devices. In recent years, it has developed rapidly, main due to its promising applications in short-wave light-emitting devices, photodetectors, as well as antiradiation, high frequency and high-energy electronic devices. Up to now, ultraviolet lasing emission,the visible emission and properties of ultradetector of ZnO have became the main topics of much researchs. In the paper, hexagonal ZnO microtubes were firstly grown on single crystal p-Si (111) substrates by hydrothermal method. The Ag, Au film electrodes were deposited respectively on ZnO by planar magnetron sputtering to form the metal/n-ZnO/metal Schottky barrier UV photodetector. The characteristics of schottky contact and UV photodetector based on hexagonal microtube ZnO were studied. Effective Schottky barrier heights were obtained by I-V,XPS measurement. It is confirmed that the presence of a large amount of surface states lead to the location of the surface fermi level at 0.35eV below the conductive band bottom. Then the characteristics of dark and photocurrent, the UV photoresponse and the quantum efficiency of the detector were also investigated. The results of testing indicated that there are an evident wide-range optical spectral responsivity and higher quantum efficiency. The effects of annealing on the microstructure and photoluminescence properties of microtube ZnO were discussed. Moreover, the orthogonalizing design method was applied to optimize the annealing process. It can be drawn a conclusion that the temperature is the most influential factor on structural characteristics. From the photoluminescence (PL) spectra of tubular ZnO, the emission peaks founded in the ultraviolet range expect to be the free exciton and bound exciton. A new emission peak between the free and bound excition was observed under low excitation intensity at room temperature, which is due to the exciton-exciton inelastic collision process (P band). In addition, a visible luminescence mechanism was also discussed.