Supporting Online Material for
Non-destructive and Rapid Evaluation of Large-area
Chemical Vapor Deposition Graphene by Dark Field
Optical Microscopy
X. H. Kong, H. X. Ji, R. D. Piner, H. F. Li, C. W. Magnuson, C. Tan, A. Ismach, H. Chou, R. S. Ruoff
a)
Department of Mechanical Engineering and the Materials Science and Engineering Program, The University
of Texas at Austin, 1 University Station C2200, Austin, Texas 78712, United States
a)
Author to whom correspondence should be addressed. E-mail: r.ruoff@mail.utexas.edu
FIG. S1. Dark field (a) and its corresponding bright field (b) optical images of bare Cu foil
without graphene coating. Only copper grain boundaries and several large dots (contamination)
are visible in both images.
1
FIG. S2. DF (a, c) and their corresponding BF (b, d) optical images of graphene on Cu foils with
90% (a, b) and 100% (c, d) coverage, respectively, with images acquired after heating in air on a
hot plate at 160 oC for 30 min. The images were captured for the same regions shown in Fig. 2.
Sub-monolayer graphene domains are distinguishable by both DF and BF optical imaging after
thermal annealing, while fully-coverage graphene can be identified only by DF imaging.
2
FIG. S3. DF (a, c, e) and their corresponding BF (b, d, f) optical images of graphene on Cu foils
at partial coverage, examined after heating in air on a hot plate at 160 oC for the indicated times.
More cracks in graphene domains are distinguished in both DF and BF optical images for the 3h
vs the 30min annealing times. All the images were captured from the same region.
FIG. S4. Bright field (a) and its corresponding Dark field (b) optical images of transferred CVD
graphene on SiO2/Si substrate (SiO2: 285 nm). On the uniform “flat” substrate, graphene or
adlayers can be identified by bright field optical imaging, yet they can hardly be seen by dark
field optical imaging. Only some high contaminants can be detected in the dark field image (b).
3
FIG. S5. Raman spectra acquired at the edges of a typical graphene domain on Cu foil. The
Raman peaks (154, 214, 510, 644 cm-1) are assigned to Cu2O15 and indicate the onset of
oxidation at the graphene domain edges.
FIG. S6. (a) DF optical image of h-BN with partial coverage on a Ni foil (50-µm thick, 99.9%
Goodfellow Corporation NI000340). The typical Raman spectrum of the h-BN films is shown in
the insert. (b) DF and (c) BF optical images of a tiny h-BN triangle domain on Ni foil. (Details of
the h-BN growth will be published soon and follows our previous report.) S1
4
References
S1
A. Ismach; H. Chou; D. A. Ferrer; Y. P. Wu; S. McDonnell; H. C. Floresca; A. Covacevich; C. Pope; R.
D. Piner; M. J. Kim; R. M. Wallace; L. Colombo; R. S. Ruoff, ACS Nano 6, 6378 (2012).
5