Preparation And Properties Research Of Graphene Field-effect Transistor

Graphene has excellent performance in such aspects as electrical, thermal and chemical, so the researchers by the governments of great attention.Combining the advantages of graphene and the sensitive charge response characteristics of graphene field-effect transistors, graphene field-effect transistor has become a new hotspot. Now, device structure and performance characterization in terms of remaining challenges, mainly due to the regulation of graphene band still have not a stable and efficient solution, resulting in the transmission performance of the field effect device is not ideal, thereby restricting the graphene further application in the field of electronics. Therefore,the regulation of the energy band structure of graphene, the preparation of the graphene field effect transistor, the optimization of the device performance, and as a basis to study the signal response performance have important research value.This paper mainly in the materials preparation and characterization of graphene field-effect transistor, the preparation and performance research of field effect devices and other aspects of research work. First to adopt chemical vapor deposition method and micro-mechanical stripping method to prepare graphene two-dimensional nanomaterials respectively, the graphene prepared by chemical vapor deposition method needs by means of wet etching transferring it to the Si/Si O2 substrate, and then characterized the graphene films of two preparation methods respectively by means of optical microscope, scanning electron microscope, atomic force microscope and Raman spectra. Then pick out graphene film having good crystal quality to prepare graphene field effect transistor. The effect transistor with graphene nano strip for conducting channel layer, based on 300 nm silica insulation for gate dielectric layer, with evaporation of Ti/Au alloy for metal electrodes. Prepared graphene field-effect transistors by photolithography, etching, coating and other semiconductor processingtechnology, improved process parameters, optimized the device structure. Finally,the paper tested the transmission characteristics, optical properties and adsorption characteristics of graphene field-effect transistors, the experimental results showed that the graphene field-effect transistor prepared is a P-type depletion type field effect transistor, which with gate voltage regulated source drain current response mechanism. The device has optical characteristics, the specific performance of the transmission characteristic curves different in light and dark conditions. However, during the test, the Dirac point of the device did not reflect,and with the increase of time when the device is placed in the air, the carrier mobility of graphene significantly became lower, mainly due to the graphene surface adsorption of a large number of PMMA and other photoresist molecules,water and other gas molecules in air. This experiment adopted the way of vacuum annealing to achieve graphene stripping of water molecules and oxygen molecules, but the annealing high temperature causes degeneration of the photoresist molecules can not be desorbed from the surface of the graphene.