Large-scale deposition of graphene on Cu foil and graphene nanopetals on carbon fiber tow have been accomplished using a custom-built roll-to-roll plasma CVD system. The effects of the process parameters (such as plasma power, gas pressure, and gas mixture of H2, CH4, N2, O2 and Ar) on graphene quality are explored systematically using statistical design of experiments. Surrogate models based on experimental data are developed to control the deposition process. Our system can produce graphene on Cu foil at a speed of 1 m/min and deposit graphene nanopetals on a 1-m long carbon fiber two. To further understand the thermochemical effects of the plasma on graphene properties, optical emission spectroscopy (OES) and electrical measurements are used to characterize H2 plasma as a function of the process parameters. Less than 50% of the set power is dissipated in the plasma, and the rotational gas temperatures (from H2 and N2+ species) can reach 1000 K depending on the average dissipation power. Results show that plasma sources can be utilized for the scalable manufacturing of carbon nanostructures without the supplemental heating of the substrate, and at a higher deposition rate because of the abundance of active carbon species in the plasma.
Majed A. Alrefae is an Assistant Professor at Royal Commission Yanbu Colleges and Institutes (RCYCI). He received his Ph.D. from Purdue University in 2018, MS from KAUST in 2013, and BS from KFUPM in 2008. He worked as a project engineer at SABIC from 2008 to 2010. At KAUST, he participated in building a spectroscopic database for hydrocarbons using FTIR, as well as measuring the ignition delay time of propene and isobutene using the high-pressure shock tube. At Purdue, he optimized and characterized a custom-built scalable roll-to-roll plasma CVD system to deposit carbon nanostructures on various flexible substrates for coating applications. Majed won the KAUST Seed Fund in 2012 and was the most improved Entrepreneurial Lead in the I-Corps Program in 2017 for commercializing carbon nanostructures. His primary research focus at RCYCI is to develop plasma processes for the deposition of carbon nanostructures for energy and water desalination applications.