Elastic electron backscattering from overlayer/substrate systems

Elastic electron backscattering probability for Au overlayers deposited on Ni were determined experimentally in the energy range 200-1000 eV. These measurements were accompanied by characterization of the overlayer structure and the mean overlayer thickness. The elastic backscattering probabilities also were derived from extensive Monte Carlo simulations of the electron transport in overlayer/substrate systems. Two overlayer structures were considered in these calculations: a uniform Au layer, and isolated Au islands located on the uncovered substrate. Analysis of the shape of Au 4d spectra with QUASES-Tougaard software indicated that the latter structure is more probable. It has been found that the experimental elastic backscattering probabilities compare better with the theoretical probabilities calculated for the island structure. The possibility of characterization of the overlayer thickness and structure from the elastic backscattering probabilities has been discussed. Copyright (C) 2001 John Wiley & Sons, Ltd.