Low-temperature Growth of Graphene by Chemical Vapor Deposition ...
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Low-temperature Growth of Graphene by Chemical Vapor Deposition using Solid and Liquid Carbon Sources Zhancheng Li, Ping Wu, Chenxi Wang, Xiaodong Fan, Wenhua Zhang, Xiaofang Zhai, Changgan Zeng,* Zhenyu Li,* Jinlong Yang, and J. G. Hou Hefei National Laboratory for Physical Sciences at Microscale and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
Graphene growth from PMMA To evaluate the uniformity of the graphene films derived from PMMA at 1000 °C in large scale, Raman mapping of the FWHM over a 76×76 µm2 area was performed (the beam size is 2µm), and the result is shown in Figure S1. The FWHM in most of the investigated area (87%) is below 40 cm-1.
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Figure S1. Raman map of the 2D band FWHM over a 76×76 µm2 area on graphene grown at 1000 °C. Graphene growth from polystyrene Besides PMMA, we also synthesized graphene from another solid carbon source, polystyrene. Polystyrene contains different molecular formula and structure from PMMA. Using the same procedure for graphene growth from PMMA, we achieved graphene films at various temperatures from polystyrene. The microstructure and quality are similar to that of PMMA derived graphene films when the growth temperature is close. This is evidenced by the Raman and SEM results of polystyrene derived graphene grown at 1000 °C and 500 °C, as shown in Figure S2a-c. The optical transmittance at 550 nm for graphene grown at 1000 °C was measured to be 96.9%. The successful growth of graphene from polystyrene further illustrates the versatility of our low-temperature CVD growth method from solid carbon precursors.
Figure S2. Polystyrene derived graphene. (a) Raman spectra of polystyrene derived graphene grown at 1000 °C and 500 °C, respectively. (b) and (c) SEM images of polystyrene derived graphene grown at 1000 °C and 500 °C respectively. The scale bars are 2 µm in (b) and (c). Graphene growth from methane For comparison with graphene growth from solid carbon sources, we attempted to grow graphene also from gaseous source (methane) at 1000 °C, 800 °C and 600 °C, respectively. The Raman spectrum and SEM image in Figure S3a and b clearly show that monolayer graphene with high quality is synthesized at 1000 °C. However for methane derived graphene grown at 800 °C, the typical Raman spectrum S2
(Figure S3a) displays a strong D band and the SEM image (Figure S3c) shows obvious structural inhomogeneity. This strongly suggests that the quality of graphene from methane source is much degraded than that of the graphene from solid carbon source at 800 °C. When the growth temperature is lowered to 600 °C, no graphene signals can be picked up in the Raman spectrum as depicted in Figure S3a. 600 °C is thus too low for graphene formation at Cu surfaces from methane. Therefore, the CVD growth route using solid carbon sources is superior than using gaseous at low temperatures. This advantage renders it a simpler and more convenient choice for industrial application in the future.
Figure S3. Methane derived graphene. (a) Raman spectra of methane derived samples grown at 1000 °C, 800 °C, and 600 °C, respectively. (b) and (c) SEM images of methane derived graphene grown at 1000 °C and 800 °C, respectively. The scale bars are 2 µm in (b) and (c).
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Low-temperature Growth of Graphene by Chemical Vapor Deposition using Solid and Liquid Carbon Sources Zhancheng Li, Ping Wu, Chenxi Wang, Xiaodong Fan, Wenhua Zhang, Xiaofang Zhai, Changgan Zeng,* Zhenyu Li,* Jinlong Yang, and J. G. Hou Hefei National Laboratory for Physical Sciences at Microscale and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
Graphene growth from PMMA To evaluate the uniformity of the graphene films derived from PMMA at 1000 °C in large scale, Raman mapping of the FWHM over a 76×76 µm2 area was performed (the beam size is 2µm), and the result is shown in Figure S1. The FWHM in most of the investigated area (87%) is below 40 cm-1.
S1
Figure S1. Raman map of the 2D band FWHM over a 76×76 µm2 area on graphene grown at 1000 °C. Graphene growth from polystyrene Besides PMMA, we also synthesized graphene from another solid carbon source, polystyrene. Polystyrene contains different molecular formula and structure from PMMA. Using the same procedure for graphene growth from PMMA, we achieved graphene films at various temperatures from polystyrene. The microstructure and quality are similar to that of PMMA derived graphene films when the growth temperature is close. This is evidenced by the Raman and SEM results of polystyrene derived graphene grown at 1000 °C and 500 °C, as shown in Figure S2a-c. The optical transmittance at 550 nm for graphene grown at 1000 °C was measured to be 96.9%. The successful growth of graphene from polystyrene further illustrates the versatility of our low-temperature CVD growth method from solid carbon precursors.
Figure S2. Polystyrene derived graphene. (a) Raman spectra of polystyrene derived graphene grown at 1000 °C and 500 °C, respectively. (b) and (c) SEM images of polystyrene derived graphene grown at 1000 °C and 500 °C respectively. The scale bars are 2 µm in (b) and (c). Graphene growth from methane For comparison with graphene growth from solid carbon sources, we attempted to grow graphene also from gaseous source (methane) at 1000 °C, 800 °C and 600 °C, respectively. The Raman spectrum and SEM image in Figure S3a and b clearly show that monolayer graphene with high quality is synthesized at 1000 °C. However for methane derived graphene grown at 800 °C, the typical Raman spectrum S2
(Figure S3a) displays a strong D band and the SEM image (Figure S3c) shows obvious structural inhomogeneity. This strongly suggests that the quality of graphene from methane source is much degraded than that of the graphene from solid carbon source at 800 °C. When the growth temperature is lowered to 600 °C, no graphene signals can be picked up in the Raman spectrum as depicted in Figure S3a. 600 °C is thus too low for graphene formation at Cu surfaces from methane. Therefore, the CVD growth route using solid carbon sources is superior than using gaseous at low temperatures. This advantage renders it a simpler and more convenient choice for industrial application in the future.
Figure S3. Methane derived graphene. (a) Raman spectra of methane derived samples grown at 1000 °C, 800 °C, and 600 °C, respectively. (b) and (c) SEM images of methane derived graphene grown at 1000 °C and 800 °C, respectively. The scale bars are 2 µm in (b) and (c).
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