Investigation On Preparation And Properties Of H/F Doped ZnO Transparent Conductive Thin Films

Transparent conductive electrodes play very important roles in today’s information and energy technologies. Transparent conductive oxidesare widely used as transparent electrodesin technical fields such as flat-panel displays, low-emissivity coatings, thin-film solar cells and light-emitting diodes. Among these materials, n-type conductive ZnO has been perceived as very good photoelectric properties. Increasing free carrier mobility is a key issue for ZnO based transparent conductive oxide films as front electrodes of photovoltaic devices. In this work, we studied ZnO films doped/co-doped with two non-metal elements (H and F), and the effect of H plasma exposure treatment on films. This work contains:1. radio frequency sputtering system was utilized for preparation of ZnO films. We incorporated H into the films by either mixing H2with Ar in deposition atmosphere or H plasma treatment. We found out that both methods reduced film resistivity to a great deal, but only films prepared with H plasma exposure treatment show high thermal stability. We attribute this stable donor to the complex of H-Vo.2. F doped ZnO films were prepared by radio frequency magnetron sputtering techinique. We found out interestingly the crystallinity didn’t increase with increasing substrate temperature. From the peak position of XRD and test results from Hall test, we infer when substrate temperature is higher than250℃, F atoms didn’t substitute O as a donor. Post annealing process helped to activate part of the inert F atoms.3. H/F co-doped ZnO films were prepared either with H2and Ar sputtering atmosphere or with post H plasma treatment. HFZO films prepared by H plasma treatment saw a soar in mobility. XPS has shown the FZO films grown with higher temperature have higher content of oxygen vacancies, facilitating the incorporation of H during post treatment and achieving stable donor. The highest mobility we get by this work is35.9cm2V-1s-1.