Comparative study of water adsorption on Ge(100)-(2×1) and GexSi1-x(100)-(2×1) by high-resolution electron-energy-loss spectroscopy

The identification of vibrational modes of OH in the electron-energy-loss spectrum of water-exposed Ge(100)-(2×1) allows us to give an alternative interpretation of high-resolution electron-energy-loss spectroscopy data of water on Ge_xSi_1-x(100)-(2×1) given in a recent publication. We show that the use of adsorbed species as markers to determine the surface composition as proposed by Broughton et al. is misleading, and that the evolution of electron-energy-loss spectra as a function of temperature can be explained in terms of mobility of adsorbed species rather than of changes in surface composition.