Studies Of Preparation And Properties Of Zinc Oxide/Graphene Composite Thin Film Transistor

Graphene is a zero band gap semiconductor, the mobility of that canreach106cm2/V s,but it can’t close the current when being applied into thin film transistor(TFT). ZnO TFT sufferfrom low mobilities, so that it often needs doping to improve the performance. If graphenecombining with ZnO was applied into TFT, their merits may be complementary. It will provide anew way of thinking for the preparation of TFT. Therefore, there is an important practicalsignificance and scientific significance for exploring the preparation, performance studies, andapplication of ZnO/graphene composite film.First, this paper studied the preparation of ZnO thin films by magnetron sputtering. Thecharacterizations of ZnO included X-ray diffraction, scanning electron microscopy, atomic forcemicroscopy, and four-probe measuring the resistivity. After comparing the before and afterannealing, different temperatures ZnO, it was found that the higher the temperature, the betterthe quality of the film. The best crystal quality was obtained at600℃. Annealing can improvethe orientation of crystal grains, and crystalline quality is also improved significantly.Second, it studied the preparation of graphene thin films by chemical vapor depositionmethod. The crystal structure and surface topography were characterized by raman spectrum andscanning electron microscopy. The influence of temperature on the structures and properties ofgraphene was investigated. It was found that the best graphene grown temperature was between750℃and800℃, higher or lower temperature both influenced the quality of graphene.Third, it was frabricated that the bottom gate top contact ZnO TFT which silicon as gateelectrode, SiO2as insulating layer, ZnO prepared by sputtering as active layer, Au deposited bymask as drain-source electrode. After comparing the quality of before and after annealing,different temperatures devices, it was found that the optimum thickness of the active layer wasbetween40and50nm, and annealing can improve the performance of the device.At last, on the base of previous experiment, it grew graphene on the surface of ZnO. Theexperimental results indicated that the additation of graphene improved the performance.However, the750℃and800℃grown graphene made the device lose the field-effect property.