SEM images of the CNFs on CF with different thicknesses of the Fe catalyst layer. (a) CNFs grown with 5 nm of Fe and (b) higher magnification of the circled area in (a). (c) CNFs grown with 10 nm of Fe on CF and (d) higher magnification of the circled area in (c).
Gao et al. Nanoscale Research Letters 2012 7:651 doi:10.1186/1556-276X-7-651