Study On Preparation Of Graphene Film With CVD Based On Solid Carbon Source

Graphene is a graphite layer which can be regarded as a carbon atom layer thickness(0.335 nm).It is a two-dimensional honeycomb lattice structure composed of carbon elements which is similar to benzene six-membered ring.The connection between carbon atoms is very flexible.Its structure is very stable.At the same time,graphene is a kind of zero-bandgap semiconductor material and play an important role in the field of microelectronics due to its excellent conductivity,thermal conductivity and mechanical properties,which make it an ideal hybrid material.Now,the CVD method based on gaseous carbon source is the main method for preparing graphene.However,the gas is not easy to control,and the gaseous carbon source(such as CH4)requires a very high temperature(usually 1000?)to crack,which make the process of controlling the preparation of graphene from gaseous carbon source is more complex.Using gaseous carbon source prepare graphene needs Cu or Ni to catalyze,and the transfer process will destroy the quality of the graphene film.All disadvantages of these methods will limit the development of graphene.Therefore,this paper uses solid carbon source,in order to prepare high-quality graphene.The main contents are as follows:In this paper,graphene films with different layers were prepared on pyroxenes of polycyclic aromatic hydrocarbons(PAHs)by pyrene.We studied three parameters,such as the graphene growth temperature,the cooling rate and the amount of carbon source to optimize the progress of prepare graphene step by step.The optimal process for preparing monolayer graphene films was selected: the growth temperature was 600 ?,the cooling rate was rapid cooling(about 25?/s),and the amount of carbon source was 0.04% carbon source per square centimeter for two drops.Graphene layers' number were controlled for growth by controlling the amount of carbon source.The growth mechanism of graphene film is also discussed.The growth mechanism of graphene is not only related to the catalytic mechanism of Cu flake,but also to the cooling rate.So,the formation of graphene is affected by both fators.Second,in order to make up for the defects in graphene samples prepared from a single solidstate carbon source,we introduced a new type of carbon source and a secondary carbon source that is easily decomposed into small molecules at high temperatures.Finally,experiments results showed that 2-naphthol has better performance than PAHs as a potential carbon source.The lipid carbon source 1-octylphosphonic acid has the ability to make up for the vacancy defects of graphene.Moreover,the ability of 1-octylphosphonic acid to compensate for defects is related to the concentration,the optimal concentration is about 10%.Finally,several graphene transfer methods were analyzed.First,a Cu film was deposited by magnetron sputtering on the target substrate and then spin-coated with solid carbon source.Then,the annealing process was omitted and the transfer step was successfully omitted.Graphene was prepared on the target substrate.The parameters of sputtering power,amount of carbon source,annealing temperature and annealing time were optimized step by step.The optimum process for preparing single-layer graphene film directly on target substrate was screened out.