Emission of positive ions from hot graphite surfaces

Date of Completion

January 2001


Physics, Condensed Matter




Significant numbers of positive ions were found to emanate from positively biased graphite samples raised to temperatures greater than 800°C. The ions were mass and energy analyzed and the relative number of ions as a function of temperature and of sample bias are presented and interpreted. The desorbed ions may be either atomic or molecular. It was found that emission is enhanced by bombardment with Ar ions, which suggests the emission is related to the concentration of surface defects and adsorption sites. The graphite samples surfaces are characterized before and after insertion in the UHV vessel by SIMS, XPS and AFM techniques. ^