The Nature Of The Ion-assisted Electron Beam Evaporation Preparation Of Nano Zno Films Study

Zinc oxide (ZnO) is a wide band gap (3.37 eV) semiconductor oxide and has a large exciton binding energy (60 meV), which allows its high efficient ultraviolet (UV) emission from the exciton and wide application to short-wavelength laser diodes and UV detectors.Until now, ZnO has been grown with various methods such as pulsed laser deposition (PLD), radio frequency magnetron sputtering (RFM) and metal-organic chemical vapour deposition (MOCVD). Here, We fabricate polycrystalline ZnO thin films and Mn-passivated ZnO:S thin films by plasma-assisted e-beam evaporation. In order to improve the quality of photoluminescence, polycrystalline ZnO thin films were prepared by thermal oxidation of metallic Zn films which are prepared by plasma-assisted e-beam evaporation. X-ray diffraction (XRD) indicates that ZnO nanoparticles exist in the as-grown Zn films, which result from O2 plasma oxidation. With the annealing temperatures increasing, the grain sizes gradually increase and the quality of the hexagonal wurtzite structural ZnO thin films is improved. The photoluminescence spectra show a strong near-band-edge emission with a weak deep level emission. Because of the quantum confinement effect and the dispersion of the grain size, the full width at half maximum (FWHM) of the photoluminescence peaks for the as-grown film is wider and the PL peak position is shorter than that of the annealed ZnO films. In order to explore the effect of plasmas on the structural and optical properties of the thin films in the process of deposition, ZnS: Mn thin films were fabricated at different values of plasma current. The results indicate that plasmas have an obvious influence on many aspects such as crystallization and thickness. Mn-passivated ZnO:S thin films were prepared by thermal oxidation of Mn-doped ZnS(ZnS:Mn) films which were prepared by e-beam evaporation. The structure and photoluminescence of films annealed at different temperature were studied, and the results indicate that S doped can affect the optical properties of ZnO.