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Supporting Information
Polymer Compatible Low-Temperature Plasma-
Enhanced Chemical Vapor Deposition of Graphene
on Electroplated Cu for Flexible Hybrid Electronics
Chen-Hsuan Lu
1
, Chyi-Ming Leu
2
, Nai-Chang Yeh
3*
.
1
Department of Applied Physics and
Materials Science, California
Institute of Technology,
Pasadena, CA, 91125, USA
2
Material and Chemical Research L
aboratories, Industrial Technol
ogy Research Institute,
Hsinchu, 31057, Taiwan
3
Department of Physics, California Institute of Technology, Pasa
dena, CA, 91125, USA
*Email: ncyeh@caltech.edu
2
Figure S1. (Top panel) Photograph of the PECVD process in progr
ess. (Bottom panel) The growth
chamber temperature change as a function of time during the PEC
VD process was recorded via
thermocouple attached on the quartz tube.
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Figure S2. Optical images, I(D)/I(G) spatial maps and histogram
s of the I(D)/I(G) spatial maps of
PECVD-grown graphene on electrop
lated Cu under different ratios
of H
2
/CH
4
: (a,e,i) H
2
/CH
4
=
12 (b,f,j) H
2
/CH
4
= 6 (c,g,k) H
2
/CH
4
= 2, and (d,h,i) H
2
/CH
4
= 1. The size of the mapping area in
(e-h), which corresponds to the red squares in (a-d), is (30
30)
m
2
. Each histogram from (i) to (l)
consists of 225 point spectra, and each point spectrum is taken
over a spot size with a radius of 0.5
m.
4
Figure S3. I(2D)/I(G) spatial maps and histograms of the I(2D)/
I(G) spatial maps of PECVD-
grown graphene on electroplated Cu under different ratios of H
2
/CH
4
flow rates: (a,e) H
2
/CH
4
= 1,
(b,f) H
2
/CH
4
= 2, (c,g) H
2
/CH
4
= 6, and (d,h) H
2
/CH
4
= 12. The size of the mapping area in (a-d)
is (30
30)
m
2
. Each histogram from (e) to (h) consists of 225 point spectra,
and each point
spectrum is taken over a spot size with a radius of 0.5
m.
5
Figure S4. Optical image comparing the appearances of the elect
roplated Cu substrate on
polyimide before and after the PECVD process.
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Figure S5. Surface morphology of electroplated Cu substrates: (
a) AFM image (top panel) and
Peak Force channel (bottom panel) of an electroplated Cu substr
ate before PECVD. (b) AFM
image of an electroplated Cu
substrate after PECVD with H
2
/CH
4
= 1. (c) AFM image of an
electroplated Cu substrate after PECVD with H
2
/CH
4
= 2. (d) AFM image of an electroplated Cu
substrate after PECVD with H
2
/CH
4
= 6. (e) AFM image of an electroplated Cu substrate after
PECVD with H
2
/CH
4
= 12. The RMS roughness of the images were indicated. The scal
e bar is 3
μm.
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Figure S6. HAADF-STEM image of the reference sample. Here a-C b
etween Cu and the protection
layer refers to amorphous carbon.
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Figure S7. Cu2p XPS spectra of (a) as-received electroplated Cu
substrate, and (b) the same
electroplated Cu substrate after dilute H
2
SO
4
etch.
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Figure S8. (Left) The circuit pattern used for the folding test
and resistance measurements. The
size for each electrical pad is (1
1) mm
2
, and the expanded image of the area indicated by the red
box is shown on the right, and the scale bar (white) is 20
m. (Right) Photograph of the equipment
for the folding test. The circuit pattern was attached to the c
enter of the equipment.
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Table S1. Electrical resistance (measured in Ω) of different sa
mples after the indicated number (N)
of folding cycles and comparison among samples grown under diff
erent H
2
/CH
4
ratios.