Figure 4: Absorbance of graphene.

(a) Diagram of the mean theoretical absorbance of graphene from 530 nm to 640 nm as a function of the Fermi level, relative to the Dirac point, and the resistance according to eqations 1, 2, 3, 4, 5, 6. Furthermore, the chart indicates the measured points, where transients were acquired, from which corresponding absorbance values can be extracted. The absorbance is plotted in units of the theoretical absorbance of graphene corresponding to πα = 0.023. (b) Considering possible contact resistances for the estimation of uncertainties, the absorbance values are evaluated along those measured paths obtained in the overlap of data and model in (a). A plateau of high absorbance is found near the Dirac Point, which starts decreasing at about 1.1 eV. It reaches negligible absorbance at about 2 V. In the negative direction, the absorbance of two measurements start to decrease in the acquired data range, while one increases further.