Fig. 3: Examination of flake quality.

a Raman spectroscopy for graphite (black), 2000 (red), 4000 (blue) and 6000 (green) processing cycles. b The I(D)/I(G) ratio plotted as a function of the Disp(G) for 6000 processing cycles. c FWHM(G) plotted as a function of the I(D)/I(G) ratio.