Research On Preparation Of ZnO-Graphene Composites Film And Its Photoresponse

Zinc oxide is a kind of wide band-gap semiconductor which has excellent physical and chemical properties. As a gapless semiconductor, graphene exhibits ultrahigh carrier mobility and fascinating transport phenomenon. Electrochemical assembly is a simple and convenient method, which has been extensively used in the synthesis of many different materials. It has several advantages, such as low processing temperature, high deposition rate, controllable film thickness and morphology. In this paper, first hexagonal cylindrical nano-ZnO film was prepared by electrochemical method and the influence of deposition parameters on the morphology and photoelectrical properties of ZnO film were studied. ZnO-Graphene composite films were synthesized by electrochemical method as well, the effects of Graphene on the morphology, optical and photoelectrical properties of the composite films were investigated.In this paper ,we explored the growth mechanism of the electrochemical preparation of ZnO nanoparticles, discussed the influence of the different electrolyte concentrations and deposition time on the structure and optical properties of ZnO nanoparticles.As the concentration of the electrolyte increase, the diameter of the ZnO nanorods increased, the grain size increased, the UV-Vis absorption spectrum red shift. We examined the photocurrent response performance of ZnO thin film under UV light, when the electrolyte concentration and deposition time increased, the photocurrent response increased. We fabricated graphene composite film by electrochemical methods. We used Raman spectroscopy, Infrared spectroscopy, X-ray photoelectron spectroscopy and X-ray diffraction techniques to comfirm that the graphene oxide in the composite film was reduced.In this paper, we found that the graphene thin film will lead a red shift in UV-Vis absorption spectra and band gap narrowing occurred. Photocurrent response studies indicated that adding graphene in composite film greatly enhanced the photocurrent response intensity. Compared with ZnO thin film (on/off ratio 20), the on/off ratio of the composite film increased to 50.