Histograms of the locally measured densities of charged impurities and vacancies in pristine and ion irradiated graphene. Charged impurities density in pristine graphene (a). Charged impurities and vacancy densities in irradiated graphene with 500 keV C+ ions at fluences 1 × 1013 cm-2 (b) and 1 × 1014 cm-2 (c), respectively.
Giannazzo et al. Nanoscale Research Letters 2011 6:109 doi:10.1186/1556-276X-6-109