A Study On Preparation And Properties Of Graphene Thin Films By RF-PECVD Method

Graphene,known as the king of new materials,has a unique two-dimensional honeycomb structure and excellent physical and chemical properties.In recent years,the governments,enterprises and research institutes of various countries have paid great attention to the study of graphene,and opened the research boom of graphene.Chemical vapor deposition is one of the most advantageous methods for large-scale preparation of high quality graphene films.RF-PECVD can achieve lower growth temperatures,better energy savings and higher productivity than conventional CVD methods.The preparation of silicon,silicon carbide and other materials using RF-PECVD system has been studied and applied for a long time,and carbon thin films such as carbon nanotubes,diamond and diamond-like films can be successfully prepared.The preparation of graphene films by this system still has a wide space to research,the quality of films is expected to be further improved,the impact of factors and films forming mechanism and other aspects should be research further.In this thesis,radiofrequency plasma enhanced chemical vapor deposition system is used,methane introduced to provide carbon source,hydrogen as the auxiliary gas,copper foil and nickel as substrate for the preparation of graphene films.Orthogonal experiments and control variable of experimental methods are applied to study the effects of gas flow rate,growth temperature,reaction pressure,RF power,deposition time and sample location during the growth of the films.The structure and morphology of the films was characterized and analyzed by field emission scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),atomic force microscopy(AFM),transmission electron microscopy(TEM),Raman spectroscopy(XRD).In addition,the hardness and coefficient of friction of the graphene prepared on the nickel substrate were tested and analyzed.The transmittance of the graphene deposited on the copper substrate was measured.The experimental results show that graphene films with multi layers are successfully prepared on the copper substrates and the nickel substrates at lower growth temperatures.The films can effectively improve the hardness of the substrates and reduce the friction coefficient of the substrate,and have good light transmission performance.