Abstract:
In this study, continuous and single crystal graphene films on copper (Cu) are synthesized by low pressure chemical vapor deposition (LPCVD) in the growth time of 40 min with the meticulously modulation of the oxygen and carbon supply in multistages synthesis processing, and graphene properties dependence on the oxygen and carbon supply is investigated. Optical microscope, field emission scanning electron microscope (FESEM) and atomic force microscope (AFM) are employed for morphology characterization while the graphene films structure are measured by transmission electron microscope (TEM), selected area electron diffraction (SAED) and Raman spectrum. It is found that double oxygen passivation (with the oxygen passivation in both nucleation and growth stages) together with the optimal flow ratio of methane and hydrogen will lead to the balance between nucleation and graphene growth rate to accomplish continuous single crystal bilayer graphene films in short time. The remarkable properties difference between the graphene processed by single and double oxygen passivation as well as the strong properties dependence on the flow ratio of methane and hydrogen with double oxygen passivation indicate that the nucleation and growth of graphene domains can be properly modulated by the oxygen passivation and carbon supply. Moreover, the graphene-based field effect transistor (FET) reveals the superior hole mobility of 4347 cm
2/(V·s). Our study provides a simple LPCVD procedure to achieve high quality graphene film on Cu in short time.