A Heat Transfer Model for Graphene Deposition on Ni and Cu Foils in a Roll-to-Roll Plasma Chemical Vapor Deposition System

Abstract

High-throughput production is a major bottleneck for integration of graphene-based technologies in existing and future applications. Here, a heat transfer model is developed to optimize large-scale deposition of graphene on Ni and Cu foils in a roll-to-roll plasma chemical vapor deposition (CVD) system. Temperature distributions in Ni and Cu foils during deposition are recorded with in situ temperature measurements using near-IR optical emission spectroscopy. The model indicates that foil movement significantly affects the temperature distribution and cooling rate of the foil. Consequently, graphene growth on Cu is limited to lower web speeds for which the foil temperature is higher and the residence time in the plasma is longer. On the other hand, graphene can be deposited on Ni at relatively higher web speeds due to moderately high diffusion rate of carbon in Ni and increased cooling rates with higher web speed. Critical limitations in the production rates of graphene using roll-to-roll CVD process exist due to significant effects of web speed on the temperature distribution of the substrate. The thermal analysis approach reported here is expected to aid in enhancing the throughput of graphene production in roll-to-roll CVD systems.

Solar–Thermal Production of Graphitic Carbon and Hydrogen via Methane Decomposition

“…We attribute the long-term degradation in process efficiency to increased flow resistance in the central region due to the decreasing porosity caused by highly enlarged and coalesced microfibers (Figure 6) that increase flow bypass through annular regions. We note that the issue of increased flow resistance could be readily addressed by adopting a continuous roll-to-roll process 44,45 that exploits the carbon fiber substrate's inherent mechanical flexibility, as shown in prior work on plasma deposition. 46 We further emphasize that, as a result of the localized heated reaction region on the carbon felt, no noticeable carbon deposition occurred on the quartz window and or on the reactor walls over the duration of testing; these issues have been common challenges in prior solar methane decomposition studies.…”