Chemical Engineering Science, Vol.201, 319-324, 2019
1.5 Minute-synthesis of continuous graphene films by chemical vapor deposition on Cu foils rolled in three dimensions
We report a high-productivity chemical vapor deposition (CVD) process of graphene by extending the reaction field to three dimensions (3D) and shortening the CVD time to a few minutes. A large Cu foil (5 x 30 cm(2)) is rolled up and set in a small reactor (3.4 cm in diameter), and a continuous graphene film is obtained uniformly in a short time (1.5 min) by using C2H4 as a more reactive carbon source than the popular CH4. The graphene transferred onto a quartz glass showed optical transmittances of 94.8-96.7% (550 nm) with sheet resistances of 0.78-1.68 K Omega sq(1) (without doping) and 0.3 K Omega sq(1) (with doping by HNO3 vapor). Compared with the previous reports for fast and/or large-scale CVD, our method realized similarly high productivity of 100 cm(2) min (1) based on the CVD time despite of the small reactor, and higher productivity of 0.03 cm(2)-graphene per cm(3) -reactor per minute based on the reactor volume and total time for high temperature processing (15 min for heating, 1 min for annealing, and 1.5 min for CVD). The knowledge obtained here on the CVD conditions and packing ratio of Cu foils (0.55 cm(2) per cm(3)-reactor) is reusable for designing large-scale graphene production processes. (C) 2019 Elsevier Ltd. All rights reserved.
Keywords:Graphene;Chemical vapor deposition;Ethylene;Three-dimensional reaction field;Short reaction time;Productivity