Counting individual atom layers in graphite – high-resolution RBS experiments on highly oriented pyrolytic graphite

Abstract

The contribution reports about recent experiments on highly oriented pyrolytic graphite (HOPG) by high-resolution Rutherford backscattering spectroscopy (RBS). By using an ion beam of 1 MeV N + up to seven individual monolayers could be identified in the RBS spectrum from such a sample. This is about twice as much as observed by other groups up to now. Since close to the surface the RBS peaks from the individual carbon layers are well separated, various quantities involved in ion–solid interaction can be determined with high precision, such as the stopping power of 1 MeV N ions in graphite and their energy straggling. Close to the surface the RBS peaks are asymmetric. This asymmetry is well explained in the framework of the Landau theory of energy straggling.