THE ELECTRONIC-STRUCTURE OF DIFFERENT FORMS OF SOLID CARBON STUDIED BY ELECTRON MOMENTUM SPECTROSCOPY

The purpose of this paper is to first give an overview of the informat ion obtained by electron momentum spectroscopy (EMS) on the electronic structure of different forms of solid carbon (single crystal graphite , polycrystalline carbon, different forms of amorphous carbon, and ful lerenes). We show for sp(2) bonded carbon that, with decreasing order, the structures observed change but certain basic features remain. sp( 3)-bonded carbon films and fullerene films both have electronic struct ures different from these graphitic films. The results of EMS are comp ared with the results of other spectroscopic and scattering techniques . It is argued that the combination of energy and momentum resolution is crucial in order to get a clear picture of the changes in the elect ronic structure due to the changes in atomic arangements. Only EMS res olves both energy and momentum for all these solids. (C) 1998 Elsevier Science B.V.