Graphene Films with Large Domain Size by a Two-Step Chemical Vapor Deposition Process

Various techniques have been developed to produce graphene and recently we discovered the synthesis of large area graphene by chemical vapor deposition of methane on Cu foils

Xuesong Li; Carl W. Magnuson; Archana Venugopal; Jinho An; Ji Won Suk; Boyang Han; Mark Borysiak; Weiwei Cai; Aruna Velamakanni; Yanwu Zhu; Lianfeng Fu; Eric M. Vogel; Edgar Voelkl; Luigi Colombo; Rodney S. Ruoff


Scholarcy highlights

  • The fundamental properties of graphene are making it an attractive material for a wide variety of applications
  • This advantage is especially true for the case of graphene growth on Cu substrates by chemical vapor deposition of methane as reported by our group and reproduced by other groups
  • It has been shown that graphene can grow across metal steps and grain boundaries, and graphene domains of a few hundred square microns have been observed on Ru substrates
  • We studied the effect of growth parameters such as temperature, methane flow rate, and methane partial pressure on the domain size of graphene grown on polycrystalline Cu
  • In order to control the graphene domain density we performed experiments where we used the precursor flux and temperature to change the degree of supersaturation of active C-containing species on the surface of the Cu to promote graphene nucleation
  • We developed an isothermal two-step growth process in which a low graphene nuclei density is set followed by achieving full graphene surface coverage by increasing the methane flow rate and partial pressure
  • A split tube furnace with a 6-inch heating zone and a 1-inch outer diameter quartz tube with gas panel having methane and hydrogen was used in a chemical vapor deposition mode to grow graphene films on Cu. The graphene synthesis process presented here is similar to that previously reported with small changes: the 25-μm thick Cu foil was first reduced and annealed at 1035 oC under 2 sccm of H2 at a pressure of 40 mTorr for 20 min to increase the Cu grain size and clean the Cu surface; the graphene growth temperature was changed to the desired value after the initial Cu cleaning and grain growth and a desired amount of methane was introduced into the growth tube; the methane partial pressure was controlled by either methane flow rate or a ball valve between the quartz tube outlet and the pump; the growth time was varied ; the methane and hydrogen gas flow and pressure are kept constant, same values as the growth process, during the furnace cool-down

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