Effects of thermal healing in cold deposited Cu films on a Ru (0001) surface

Abstract

The influence of defects in thin metal films was studied for Cu films deposited on a Ru (001) surface at 40 K by means of angular resolved photoelectron spectroscopy (ARPES), photoemission of adsorbed xenon (PAX) and work function measurements. The cold deposited films are dominated by defects and the defect concentration at their surfaces is hardly inffluenced by annealing up to 150 K. Above 150 K defects are healed out resulting in strong shifts in the PAX spectra and work function changes. An annealed 8 nm films exhibits a clear Cu(111) valence band structure and angular integrated photoemission spectra show the density of state (DOS) of bulk copper. The coldly deposited 8 nm Cu film is characterized by a drastically reduced DOS at electron binding energies larger than 3 eV as well as by a lower dispersion of the Cu (3d) bands. The properties of a 3 ML Cu film, as obtained by PAX, are at all temperatures identical to the properties of a thick Cu film (8 nm). © 1992.