The Preparation Of Cu, H-codoped ZnO Thin Films By Magnetron Sputtering And Their Transparent Conductive Properties

It had been confirmed that H doping or Cu doping can significantly modify theoptical, electrical or magnetic properties of ZnO thin films. However, H, Cu-codopedZnO thin films have not been extensivly investigated up to now although severalstudies reported have shown that they have potential application in optoelectronicdevices. This thesis intended to prepare ZnO-based thin films by magnetron sputteringmethod. By changing Cu content in ZnO target and introducing H2with differentfluxes into chamber during sputtering process, the ZnO thin films codoped withdifferent contents of H and Cu were prepared. The microstructural, optical andelectrical properties of the thin films were investigated, and then the optimizedprocess parameters for the films with excellent transparent conductive properties wereobtained. At the same, H and Cu doping mechanisms for H, Cu-codoped ZnO thinfilms were discussed, which will provide a reference for further research andapplication.First, the effects of H2flux and Cu content （0，0.5and2at%）in ZnO target on thestructure and properties of the films prepared at substrate temperature of150and300oC were comparatively investigated. When the substrate temperature is150oC, it isfound that the films prepared from three different targets have only (002) diffractionpeak and lowest resistivity of10-2Ω cm at suitable H2fluxes; all the films have theaverage transmittance in visible range of about90%except that the films from2at.%Cu-doped target show obvious decreased transmittance at the H2flux above acertain value. When the substrate temperature is300oC, it is observed that the lowestresistivity is basically achieved at maximum value of H2flux; all the films have theaverage transmittance in visible range of about80%except that the films preparedfrom2at.%Cu-doped ZnO target at H2flux of4.5and6sccm.Secondly, the effects of aging and vacuum annealing treatment on the conductiveproperties of H, Cu-codoped ZnO films were further investigated. The resultsindicate only the films prepared from2at.%Cu-doped ZnO target show good conductive stability, that is the resistivity of the films has no obvious increase withaging or vacuum annealing treatment, at the substrate temperature of150oC. But atthe substrate temperature of300oC, almost the films exhibit good conductivestability.Finally，after vacuum annealing treatment, the resistivity of three types of the filmsis greatly increased, but their conductive stability with aging is obviously improved atthe same time.