STM visualization of the different types of defects on graphite surface irradiated with the low-energy argon ions

Highly oriented pyrolytic graphite (HOPG) was irradiated with argon ions at energies of 45 and 55 eV. Small ion doses were applied to the sample to en sure that single defects would not interfere. Both the sample irradiation a nd the STM measurements were carried out under the UHV conditions. Two diff erent types of features (dark and bright) were found simultaneously in the STM image inside the: single frame. The dark features can transform irrever sibly to the bright ones during the scanning, or can disappear. Judging by defect transformation, it is possible to assume that the dark defects are v acancies, while the bright ones are either Ar interstitials or Vacancies wi th some atomic duster adsorbed on them.