Raman Spectra in Irradiated Graphene: Line Broadening, Effects of Aging and Annealing

The results of measurements of the Raman spectra in the same group of monolayer graphene samples, successively subjected to irradiation with different ions, prolonged aging, and annealing under different conditions, are considered. Changes in the position, width, and intensity of the Raman lines are analyzed in the study of the following problems: comparison of the results of irradiation with various ions, the influence of prolonged aging on the spectra of irradiated samples, the mechanism of broadening of Raman scattering lines caused by an increase in the density of radiation defects, the consequences of annealing of radiation damages in vacuum and in the atmosphere of the forming gas, the contribution of doping and lattice deformation to the shift of the position of the Raman lines after annealing. The results obtained made it possible to determine the level of stability of defects introduced by radiation, to reveal the possibility of restoring the damaged lattice using annealing. Since the results relate to graphene deposited on a widely used SiO2/Si substrate, they may be of interest when using ion irradiation to change the properties of graphene in appropriate devices.