Ions and carbon nanostructures

Abstract

First experiments on swift ion irradiation of highly oriented pyrolythic graphite led to formation of carbon nanotubes (CNT) at the cascade eruption points. CNT length was in the micron range, which corresponded to an explosive crystallization of the carbon plume with about sound velocity. Multiplicity of CNT walls depended on cascade density: single wall CNTs were formed for approx. 200 MeV Xe ions, while multiwall CNTs for Kr, Ne ions of similar energy. Ion beam created defects were clearly visible on scanning tunneling microscopy (STM) images with atomic resolution. Second part of the paper deals with results of ion irradiation to sensitize CNT-s to reach, e.g. gas sensing properties using mainly changes in electrical conductivity of the bunch of CNTs. A third part of the paper contains some results on irradiated graphene. A new nanolithography technique of graphene used STM as a tool for nanostructuring graphene with crystallographic orientation control and line width of the order of few nanometers. The process enables to produce few nm wide stripes with precise crystallographic orientation.