Figure 4
From: High-speed roll-to-roll manufacturing of graphene using a concentric tube CVD reactor
Influence of substrate velocity on graphene coverage, as shown by SEM images after CVD treatment of Cu. The large areas of similar contrast indicate Cu grains (with boundary indicated by the dashed lines in the 75 mm/min image) and the local dark regions within the individual grains correspond to graphene. Nanoscale domains of graphene are formed at short growth times (i.e., as observed for high substrate velocity, 500 mm/min) and coalesce to form larger domains for longer growth times (i.e., at lower substrate velocity). Prominent diagonal grooves in the 25, 250 and 500 mm/min images are due to the surface processing of the foil. High-magnification image of 500 mm/min sample most clearly shows isolated domains within a Cu grain.
