Raman D-band in the irradiated graphene: Origin of the non-monotonous dependence of its intensity with defect concentration

Raman spectroscopy is one of the experimental techniques more used in studying irradiated carbon nanostructures, in particular graphene, due to its high sensibility to the presence of defects in the crystalline lattice. Special attention has received the variation of the intensity of the Raman D-band of graphene with the concentration of defects produced by irradiation. Nowadays, there are enough experimental evidences about the non-monotonous character of that dependence, but the explanation of this behavior is still controversial. In the present work we developed a simplified mathematical model to obtain a functional relationship between these two magnitudes and showed that the non-monotonous dependence is intrinsic to the nature of the D-band and that it is not necessarily linked to amorphization processes. The obtained functional dependence was used to fit experimental data taken from other authors. The determination coefficient of the fitting was .