Magnetron Sputtering Doped Crystal Structure And Optical Properties Of Zno Thin Films

ZnO is a promisingⅡ-Ⅵcompound semiconductor material with the properties of direct wide-band gap (3.37eV at 300K), has a large exciton binding energy at room temperature (60meV). It has attracted intensive research effort and becomes the research hotspot. Therefore, it has a broad application on UV light emitters, piezoelectric devices, light detect device and solar cell.Recently, Si is still the photovoltaic materials on use at large, however, the contradiction between the transform efficiency and product cost restricts its mass manufacture and application. Therefore, it is important to develop a new generation of solar cell materials with low cost and simple product technics.It is rarely reported about the preparation of ZnO on ITO by RF-mangentron sputtering and the study of its photoresponse ability. In this article, ZnO thin films are deposited on ITO by RF-sputtering. We took advantage of electrochemistry test instrument and solar simulation to determine the photocurrent of ZnO/ITO. We studied the influence of substrate temperature,Al doping,N doping and Al-N co-doping on photoresponse and the transform mechanism. The result is better than other report in terms of photocurrent and response time, which means that ZnO/ITO under simple fabrication technique has a great application potential on solar cell and initiated a new approach for the application of ZnO on solar cell. Also in this article, we investigated the influence of substrate temperature on the crystal structure, surface morphology and optical electronic properties of the polycrystalline ZnO thin films on different substrates. In the meantime, we changed the target to a ZnO:Al target doped with 2% Al, or changed the gas atmosphere to 50% N2/(Ar+N2), and realized the Al doping,N doping and Al-N co-doping. We studied the influence of those doping on the crystal structure, surface morphology and optical electronic properties of the polycrystalline ZnO thin films on different substrates. The crystal structure, surface morphology, cross sectional morphology, optical transmittance and photoluminescence were obtained by X-ray diffraction(XRD), Atomic force microscope(AFM), Scan electron spectroscopy(SEM), UV-vis spectrophotometer and Fluorescence spectrophotometer, respectively. The doping did not change the crystal structure, Al and N replaced the positions of Zn and O in the ZnO crystal structure. We also found that the Al doping increased the optical band gap of ZnO thin films, but the N doping reduced the band gap. In the meantime, Al doping,N doping and Al-N co-doping, all of them increased the concentration of defects and the concentration scattering centers in the polycrystalline ZnO thin films, and reduced the ability of photoresponse.