Effect of sulfur on the initial stages of oxide growth on Ni(111)

Abstract

The effects of pre-adsorbed sulfur (S) on the initial stages of oxidation, at 300 and 440 K, of a Ni(111) surface have been studied using Auger electron spectroscopy (AES) and low-energy electron diffraction (LEED). The oxygen (O) uptake rate was measured as a function of oxygen exposure at various S precoverages. It was observed that submonolayer amounts of pre-adsorbed S strongly retard the oxide nucleation and growth rate, but do not seem to alter the final oxide thickness. An island growth model describes the oxide growth kinetics at 300 K very well, but is not so successful for the 440 K data. Both the magnitude of the S coverage and temperature affect the degree of oxide epitaxy on Ni(111).