Atomic Vacancy Engineering of Graphitic Surfaces: Controlling the Generation and Harnessing the Migration of the Single Vacancy

The selective introduction of atomic-scale defects with tunable density in graphite, graphene, and carbon nanotubes is highly desirable, as it could afford a better control of their properties, but difficult to realize in practice. Here, we present a plasma-based chemical approach for the selective generation of single vacancies on the graphite surface with densities between similar to 5 x 10(2) and 3 x 10(5) mu m(-2) and apply it to the investigation of the migration behavior of this type of defect. Through scanning tunneling microscopy (STM) observation of vacancy-decorated graphite surfaces heat-treated to several different temperatures, the migration barrier for the single vacancy was deduced to be similar to 0.9-1.0 eV but could be reduced to similar to 0.7 eV via interaction with the STM tip. This constitutes the first direct experimental measurement of the migration barrier for the single vacancy in graphite that is consistent with theoretical calculations.