Effect of a Balanced Concentration of Hydrogen on Graphene CVD Growth

Figure 4

Scanning electron microscope pictures of graphene domains on copper foil after (a) 20′ growth. Four lobes with dendritic extension (blue circle) and butterfly-like (red circle) graphene islands are grown with a size of 40 μm. (b) 40 minutes growth. The nucleation density is higher but the domains are etched because of the high hydrogen concentration. (c) 40′ growth with reduced hydrogen flow. During the first 20′ of growth, the hydrogen flow was 20 sccm and in the rest of the process H₂ flow was stopped. This method avoids the etching observed in the previous sample. Most of the substrate appeared covered with graphene. The scale bar is always at 100 μm.

(a)

(b)

(c)