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Methods
Graphene growth and fabrication of patterned graphene anodes. Copper foils in
the inner quartz tubes were inserted into a tubular quartz tube of a CVD system
before the growth process. The foils were then heated to 1,000 8C with 10 s.c.c.m.
flow of H2 gas under 80 mtorr of pressure for 30 min. In the same flow of H2 gas and
pressure, the copper foils were annealed at 1,000 8C for 30 min. In the growth step,
the precursor gas CH4 (15 s.c.c.m.) was injected at a pressure of 1.6 torr for
30 min. After this step, the copper foils were rapidly cooled to room temperature.
This thermal CVD process based on copper catalytic material resulted in a graphene
film with a uniform monolayer coverage of .95% with high quality.
To form the multilayered graphene film using graphene films on copper foils, a
coating of PMMA or thermal release tape (TRT) was applied onto the graphene/
copper foil as the first step of the transfer process. After etching of the copper foil, we
delivered the polymer/graphene film onto the other graphene/copper foil instead of
a target substrate, because the repetition of this process resulted in the formation of
multilayered graphene without an additional polymer-coating process. One of the
advantages of this procedure is avoiding any residual polymer residues between each
layer in the final multilayered graphene. When the desired number of stacks was
achieved, it was transferred onto the target substrate (in this work, PET). The
PMMA support was effectively removed using acetone boiled up to 80 8C. The TRT
support was detached by removing the adhesive force holding the graphene using a
90 8C thermal treatment performed with a roll-to-roll laminator.

To form the graphene anode pattern without organic residue, we used a shadow
mask and oxygen plasma etching (70 mtorr, 100 W, 3 s) instead of a
photolithography process. If a microscale pattern were required, a photolithography
procedure could be added to this procedure. The graphene films were p-doped with
HNO3 or AuCl
3 to increase their conductivity (changes of sheet resistance with time
is shown in Supplementary Fig. S10).
Although the conductivities of the present graphene films made using the CVD
method are moderate, it might be possible to further improve the electrical
properties by developing a growth mechanism for large grains with a well-connected
grain boundary and a method to transfer a very flat, defect-free graphene film to a
substrate without generating ripples and cracks, which in turn would lead to further
improvement of the organic device performance.
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8814402

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成段就算了,你不可能都不会吧?
2楼2012-11-10 11:24:32
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