Investigation of the Strongly Correlated Two-Hole State of Copper in Resonant Photoemission States of Chalcogenide Materials for Photovoltaics

Abstract

The processes of direct and two-stage production of photoelectrons and the participation of internal states in the spectra of electrons from valence bands with resonant photoemission in copper chalcogenides Cu(In,Ga)Se2 have been studied experimentally. Final two-hole states in photoemission have been obtained at the threshold excitation of the Cu 2p level. The strong interaction of holes leads to the multiplet splitting of these states. The value of the Hubbard repulsion of holes on the copper atom has been found to be 7 eV.