EVOLUTION OF K-GRAPHITE, RB-GRAPHITE AND CS-GRAPHITE INTERCALATION COMPOUNDS SURFACES UNDER CONTROLLED OXIDIZATION - AN XPS STUDY

The evolution of XPS spectra of K-, Rb- and Cs-GICs of stage 1,2 and 3 , when their cleaved surfaces are submitted to well controlled oxidiza tion is presented. The results confirm the existence of the alkali sur face species previously observed on clean surfaces and the surface evo lution under oxidization is described through diffusion of the metalli c atoms from inner interlayers onto the surface. A clear explanation m ay, thus, be given for the apparent superficial enrichment in alkali c laimed in various previous papers.