DENSITY OF STATES MODIFICATION IN AMORPHOUS AND HYDROGENATED AMORPHOUS GERMANIUM AND THEIR EFFECT ON 3d CORE LEVELS BINDING ENERGY

By using photoemission and partial yield spectroscopies the conduction band edge, the valence band and the 3d core levels of amorphous germanium hydrogenated and nonhydrogenated are studied and compared to that of crystalline Ge. We measure a 0.25 eV shift of the 3d core levels of amorphous Ge as compared to crystalline Ge whereas a smaller shift and a slight line - broadening are found in hydrogenated amorphous samples with low H content. These results are discussed in term of the contribution to the self-energy due to relaxation of the valence electrons when a core hole is created.