X-RAY AND UV VALENCE-BAND PHOTOEMISSION OF CARBON-FILMS

The widely differing properties of amorphous carbon films originate fr om the different s-p hybridization schemes possibly occurring in the C -C bond For the study of such systems, an approach is suggested that p rovides direct access to these different types of s-p hybridization vi a a separate mapping of the s and p partial density of states (DOS) co ntributing to the total valence band (VB) DOS in carbon materials. Bot h x-ray and UV-excited VB spectra are needed to this end: the dependen ce of photoionization cross-sections on photon energy in fact makes x- ray-excited VB photoemission essentially a probe of the s-DOS, and UV- excited VB photoemission essentially a probe of the p-DOS. (C) 1998 Jo hn Wiley & Sons, Ltd.