Chemical vapour deposition of carbon-containing precursors on metal substrates is currently the most promising route for the scalable synthesis of large-area, high-quality graphene films1. However, there are usually some imperfections present in the resulting films: grain boundaries, regions with additional layers (adlayers), and wrinkles or folds, all of which can degrade the performance of graphene in various applications2,3,4,5,6,7. There have been numerous studies on ways to eliminate grain boundaries8,9 and adlayers10,11,12, but graphene folds have been less investigated. Here we explore the wrinkling/folding process for graphene films grown from an ethylene precursor on single-crystal Cu–Ni(111) foils. We identify a critical growth temperature (1,030 kelvin) above which folds will naturally form during the subsequent cooling process. Specifically, the compressive stress that builds up owing to thermal contraction during cooling is released by the abrupt onset of step bunching in the foil at about 1,030 kelvin, triggering the formation of graphene folds perpendicular to the step edge direction. By restricting the initial growth temperature to between 1,000 kelvin and 1,030 kelvin, we can produce large areas of single-crystal monolayer graphene films that are high-quality and fold-free. The resulting films show highly uniform transport properties: field-effect transistors prepared from these films exhibit average room-temperature carrier mobilities of around (7.0 ± 1.0) × 103 centimetres squared per volt per second for both holes and electrons. The process is also scalable, permitting simultaneous growth of graphene of the same quality on multiple foils stacked in parallel. After electrochemical transfer of the graphene films from the foils, the foils themselves can be reused essentially indefinitely for further graphene growth.
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The data sets generated during the current study, and/or analysed during the current study, are available from the corresponding author upon reasonable request.
Li, X. et al. Large-area synthesis of high-quality and uniform graphene films on copper foils. Science 324, 1312–1314 (2009).
Zhu, W. et al. Structure and electronic transport in graphene wrinkles. Nano Lett. 12, 3431–3436 (2012).
Wang, B. et al. Camphor-enabled transfer and mechanical testing of centimeter-scale ultrathin films. Adv. Mater. 30, 1800888 (2018).
Huang, M. et al. Highly oriented monolayer graphene grown on a Cu/Ni(111) alloy foil. ACS Nano 12, 6117–6127 (2018).
Chen, S. et al. Thermal conductivity measurements of suspended graphene with and without wrinkles by micro-Raman mapping. Nanotechnology 23, 365701 (2012).
Li, X., Colombo, L. & Ruoff, R. S. Synthesis of graphene films on copper foils by chemical vapor deposition. Adv. Mater. 28, 6247–6252 (2016).
Luo, D. et al. Adlayer-free large-area single crystal graphene grown on a Cu(111) foil. Adv. Mater. 31, 1903615 (2019).
Wang, M., Luo, D., Wang, B. & Ruoff, R. S. Synthesis of large-area single-crystal graphene. Trends Chem. 3, 15–33 (2021).
Zhang, J. et al. Controlled growth of single-crystal graphene films. Adv. Mater. 32, 1903266 (2020).
Pang, J. et al. Oxidation as a means to remove surface contaminants on Cu foil prior to graphene growth by chemical vapor deposition. J. Phys. Chem. C 119, 13363–13368 (2015).
Han, Z. et al. Homogeneous optical and electronic properties of graphene due to the suppression of multilayer patches during CVD on copper foils. Adv. Funct. Mater. 24, 964–970 (2014).
Han, G. H. et al. Influence of copper morphology in forming nucleation seeds for graphene growth. Nano Lett. 11, 4144–4148 (2011).
Zhang, Y. et al. Defect-like structures of graphene on copper foils for strain relief investigated by high-resolution scanning tunneling microscopy. ACS Nano 5, 4014–4022 (2011).
Wang, W., Yang, S. & Wang, A. Observation of the unexpected morphology of graphene wrinkle on copper substrate. Sci. Rep. 7, 8244 (2017).
Tripathi, M. et al. Structural defects modulate electronic and nanomechanical properties of 2D materials. ACS Nano 15, 2520–2531 (2021).
Hattab, H. et al. Interplay of wrinkles, strain, and lattice parameter in graphene on iridium. Nano Lett. 12, 678–682 (2012).
Lee, J.-H. et al. Wafer-scale growth of single-crystal monolayer graphene on reusable hydrogen-terminated germanium. Science 344, 286–289 (2014).
Choi, J.-K. et al. Growth of wrinkle-free graphene on texture-controlled platinum films and thermal-assisted transfer of large-scale patterned graphene. ACS Nano 9, 679–686 (2015).
Zhang, X. et al. Epitaxial growth of 6 in. single-crystalline graphene on a Cu/Ni (111) film at 750 °C via chemical vapor deposition. Small 15, 1805395 (2019).
Deng, B. et al. Wrinkle-free single-crystal graphene wafer grown on strain-engineered substrates. ACS Nano 11, 12337–12345 (2017).
Zhang, Y. et al. Batch production of uniform graphene films via controlling gas-phase dynamics in confined space. Nanotechnology 32, 105603 (2021).
Polsen, E. S., McNerny, D. Q., Viswanath, B., Pattinson, S. W. & John Hart, A. High-speed roll-to-roll manufacturing of graphene using a concentric tube CVD reactor. Sci. Rep. 5, 10257 (2015).
Wang, Y. et al. Electrochemical delamination of CVD-grown graphene film: toward the recyclable use of copper catalyst. ACS Nano 5, 9927–9933 (2011).
Deng, B. et al. Anisotropic strain relaxation of graphene by corrugation on copper crystal surfaces. Small 14, 1800725 (2018).
Kang, J. H. et al. Strain relaxation of graphene layers by Cu surface roughening. Nano Lett. 16, 5993–5998 (2016).
Suh, I.-K., Ohta, H. & Waseda, Y. High-temperature thermal expansion of six metallic elements measured by dilatation method and X-ray diffraction. J. Mater. Sci. 23, 757–760 (1988).
Ferrari, A. C. et al. Raman spectrum of graphene and graphene layers. Phys. Rev. Lett. 97, 187401 (2006).
Lee, J. E., Ahn, G., Shim, J., Lee, Y. S. & Ryu, S. Optical separation of mechanical strain from charge doping in graphene. Nat. Commun. 3, 1024 (2012).
Zabel, J. et al. Raman spectroscopy of graphene and bilayer under biaxial strain: bubbles and balloons. Nano Lett. 12, 617–621 (2012).
Lee, G.-H. et al. High-strength chemical-vapor–deposited graphene and grain boundaries. Science 340, 1073–1076 (2013).
Yi, D. et al. What drives metal-surface step bunching in graphene chemical vapor deposition? Phys. Rev. Lett. 120, 246101 (2018).
Leong, W. S. et al. Paraffin-enabled graphene transfer. Nat. Commun. 10, 867 (2019).
Huang, M. et al. Large-area single-crystal AB-bilayer and ABA-trilayer graphene grown on a Cu/Ni(111) foil. Nat. Nanotechnol. 15, 289–295 (2020).
Kim, S. et al. Realization of a high mobility dual-gated graphene field-effect transistor with Al2O3 dielectric. Appl. Phys. Lett. 94, 062107 (2009).
Jin, S. et al. Colossal grain growth yields single-crystal metal foils by contact-free annealing. Science 362, 1021 (2018).
This work was supported by the Institute for Basic Science (IBS-R019-D1). We appreciate discussions with R. Huang (UT Austin) and K. Duck Park and H. Lee of UNIST.
The Institute for Basic Science has filed a patent application (KR 10-2021-0095514) that lists Meihui Wang, D.L. and R.S.R. as inventors. Other than this, the authors declare no competing interests.
Peer review information Nature thanks Cedric Huyghebaert, Jeehwan Kim and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Peer reviewer reports are available.
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Wang, M., Huang, M., Luo, D. et al. Single-crystal, large-area, fold-free monolayer graphene. Nature 596, 519–524 (2021). https://doi.org/10.1038/s41586-021-03753-3