HYBRIDIZATION OF 3D STATES OF PHOTODOPED CU IN AMORPHOUS GESE2 BY RESONANT PHOTOEMISSION SPECTROSCOPY

Photoemission spectra of Cu-photodoped a-GeSe2 have been measured at several excitation energies near Cu 3p core-excitation threshold in detail. In the spectra, the Cu 3d satellite is clearly observed, and from its position it is concluded that the valency of Cu is monovalent. The satellite intensity shows a Fano-type resonance near the Cu 3p threshold. The resonance indicates that the Cu 3d state mixes with the Se 4p state to some degree. These results support a recent structural model in which photodoped Cu makes one covalent and three dative bonds to four surrounding Se atoms in a-GeSe2. © 1990 The American Physical Society.