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High-speed roll-to-roll manufacturing of graphene using a concentric tube CVD reactor.

Polsen ES, McNerny DQ, Viswanath B, Pattinson SW, John Hart A - Sci Rep (2015)

Bottom Line: We show that a smooth isothermal transition between the reducing and carbon-containing atmospheres, enabled by injection of the carbon feedstock via radial holes in the inner tube, is essential to high-quality roll-to-roll graphene CVD.We discuss how the foil quality and microstructure limit the uniformity of graphene over macroscopic dimensions.We conclude by discussing means of scaling and reconfiguring the CTCVD design based on general requirements for 2-D materials manufacturing.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical Engineering, University of Michigan, 2350 Hayward St., Ann Arbor, MI 48109, USA.

ABSTRACT
We present the design of a concentric tube (CT) reactor for roll-to-roll chemical vapor deposition (CVD) on flexible substrates, and its application to continuous production of graphene on copper foil. In the CTCVD reactor, the thin foil substrate is helically wrapped around the inner tube, and translates through the gap between the concentric tubes. We use a bench-scale prototype machine to synthesize graphene on copper substrates at translation speeds varying from 25 mm/min to 500 mm/min, and investigate the influence of process parameters on the uniformity and coverage of graphene on a continuously moving foil. At lower speeds, high-quality monolayer graphene is formed; at higher speeds, rapid nucleation of small graphene domains is observed, yet coalescence is prevented by the limited residence time in the CTCVD system. We show that a smooth isothermal transition between the reducing and carbon-containing atmospheres, enabled by injection of the carbon feedstock via radial holes in the inner tube, is essential to high-quality roll-to-roll graphene CVD. We discuss how the foil quality and microstructure limit the uniformity of graphene over macroscopic dimensions. We conclude by discussing means of scaling and reconfiguring the CTCVD design based on general requirements for 2-D materials manufacturing.

No MeSH data available.


Influence of substrate velocity on roll-to-roll graphene synthesis on copper foil. a) Average Raman spectra for each of the five velocities tested, from 25 mm/min to 500 mm/min. A polynomial fit of the background signal was subtracted from the raw Raman spectra, resulting in the spectra shown. Additional post processing (see Methods) was applied to each spectrum prior to analysis of the peak intensities. An example post-processed spectrum is overlaid on the 25 mm/min background subtracted data (red). b) Average I2D/IG and IG/ID values versus substrate velocity. c) Comparison of Raman spectra (25 mm/min) before and after transfer to SiO2 (see Methods).
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f3: Influence of substrate velocity on roll-to-roll graphene synthesis on copper foil. a) Average Raman spectra for each of the five velocities tested, from 25 mm/min to 500 mm/min. A polynomial fit of the background signal was subtracted from the raw Raman spectra, resulting in the spectra shown. Additional post processing (see Methods) was applied to each spectrum prior to analysis of the peak intensities. An example post-processed spectrum is overlaid on the 25 mm/min background subtracted data (red). b) Average I2D/IG and IG/ID values versus substrate velocity. c) Comparison of Raman spectra (25 mm/min) before and after transfer to SiO2 (see Methods).

Mentions: In Fig. 3a, we show a typical Raman spectrum for each speed, based on data collected at 27 locations across each sample. Characteristic D, G and 2D peaks were observed at all speeds, and the D peak intensity increased while the G peak intensity decreased with increasing translation speed. Accordingly, the I2D/IG ratio decreases as the velocity increases (Fig. 3b), implying either an increasing number of graphene layers or an increase in the density of graphene edges. Two-dimensional Raman maps of the same substrates also indicate that the I2D/IG ratio trend with velocity is consistent across larger sample areas (see Supporting Information, Fig. S1). A similar inverse relationship is observed between the IG/ID ratio and substrate velocity (Fig. 3b), indicating an increase in defects or free edges27. Additionally, the average full width at half-maximum (FWHM) values of the 2D peaks increase with speed from 36 to 79 cm−1 (see Supporting Information, Fig. S2), which may indicate an increase in the number of graphene layers (i.e., from monolayer to multi-layer graphene), or increasing edge defect density at higher substrate velocity2528.


High-speed roll-to-roll manufacturing of graphene using a concentric tube CVD reactor.

Polsen ES, McNerny DQ, Viswanath B, Pattinson SW, John Hart A - Sci Rep (2015)

Influence of substrate velocity on roll-to-roll graphene synthesis on copper foil. a) Average Raman spectra for each of the five velocities tested, from 25 mm/min to 500 mm/min. A polynomial fit of the background signal was subtracted from the raw Raman spectra, resulting in the spectra shown. Additional post processing (see Methods) was applied to each spectrum prior to analysis of the peak intensities. An example post-processed spectrum is overlaid on the 25 mm/min background subtracted data (red). b) Average I2D/IG and IG/ID values versus substrate velocity. c) Comparison of Raman spectra (25 mm/min) before and after transfer to SiO2 (see Methods).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4440526&req=5

f3: Influence of substrate velocity on roll-to-roll graphene synthesis on copper foil. a) Average Raman spectra for each of the five velocities tested, from 25 mm/min to 500 mm/min. A polynomial fit of the background signal was subtracted from the raw Raman spectra, resulting in the spectra shown. Additional post processing (see Methods) was applied to each spectrum prior to analysis of the peak intensities. An example post-processed spectrum is overlaid on the 25 mm/min background subtracted data (red). b) Average I2D/IG and IG/ID values versus substrate velocity. c) Comparison of Raman spectra (25 mm/min) before and after transfer to SiO2 (see Methods).
Mentions: In Fig. 3a, we show a typical Raman spectrum for each speed, based on data collected at 27 locations across each sample. Characteristic D, G and 2D peaks were observed at all speeds, and the D peak intensity increased while the G peak intensity decreased with increasing translation speed. Accordingly, the I2D/IG ratio decreases as the velocity increases (Fig. 3b), implying either an increasing number of graphene layers or an increase in the density of graphene edges. Two-dimensional Raman maps of the same substrates also indicate that the I2D/IG ratio trend with velocity is consistent across larger sample areas (see Supporting Information, Fig. S1). A similar inverse relationship is observed between the IG/ID ratio and substrate velocity (Fig. 3b), indicating an increase in defects or free edges27. Additionally, the average full width at half-maximum (FWHM) values of the 2D peaks increase with speed from 36 to 79 cm−1 (see Supporting Information, Fig. S2), which may indicate an increase in the number of graphene layers (i.e., from monolayer to multi-layer graphene), or increasing edge defect density at higher substrate velocity2528.

Bottom Line: We show that a smooth isothermal transition between the reducing and carbon-containing atmospheres, enabled by injection of the carbon feedstock via radial holes in the inner tube, is essential to high-quality roll-to-roll graphene CVD.We discuss how the foil quality and microstructure limit the uniformity of graphene over macroscopic dimensions.We conclude by discussing means of scaling and reconfiguring the CTCVD design based on general requirements for 2-D materials manufacturing.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical Engineering, University of Michigan, 2350 Hayward St., Ann Arbor, MI 48109, USA.

ABSTRACT
We present the design of a concentric tube (CT) reactor for roll-to-roll chemical vapor deposition (CVD) on flexible substrates, and its application to continuous production of graphene on copper foil. In the CTCVD reactor, the thin foil substrate is helically wrapped around the inner tube, and translates through the gap between the concentric tubes. We use a bench-scale prototype machine to synthesize graphene on copper substrates at translation speeds varying from 25 mm/min to 500 mm/min, and investigate the influence of process parameters on the uniformity and coverage of graphene on a continuously moving foil. At lower speeds, high-quality monolayer graphene is formed; at higher speeds, rapid nucleation of small graphene domains is observed, yet coalescence is prevented by the limited residence time in the CTCVD system. We show that a smooth isothermal transition between the reducing and carbon-containing atmospheres, enabled by injection of the carbon feedstock via radial holes in the inner tube, is essential to high-quality roll-to-roll graphene CVD. We discuss how the foil quality and microstructure limit the uniformity of graphene over macroscopic dimensions. We conclude by discussing means of scaling and reconfiguring the CTCVD design based on general requirements for 2-D materials manufacturing.

No MeSH data available.