Formation and annealing effect for close-packed Ge/Cu(111) layers

Abstract

Growth and annealing effects of Ge/Cu(111) ultrathin films as deposited at ambient temperature have been studied using Auger electron spectroscopy and low-energy electron diffraction techniques. Ge/Cu(111) system shows a 1×1 structure up to 5 monolayers as deposited at 300 K. The kinetic energy of Cu L3M45M45 Auger electrons shifts to a lower value upon deposition of Ge overlayers. This could be explained by the electric charge transfer between Ge and Cu atoms. From the intensity ratio change of Auger signals (IGe/ICu), significant interdiffusion of Ge/Cu(111) films occurs around 375 K. Owing to the formation of a Cu-rich surface layer, the Cu L3M45M45 peak restores to the initial kinetic energy of a clean Cu(111) surface at 500 K.