Schematics of defects and impurities and the formation of multi-quantum dots. (a) Schematic of defects and impurities on a single-layer graphene flake before hydrogen plasma treatment. (b) Schematic of the formation of multi-quantum dots on hydrogen graphene. The white regions, containing the defects and impurities, enclosed by the hydrogen atoms (the green dots) represent graphene multi-quantum dots.
Chuang et al. Nanoscale Research Letters 2012 7:459 doi:10.1186/1556-276X-7-459