The presence of silicon on the surface of platinum films evaporated onto a number of silicon-containing supports

Abstract

Photoelectric work function measurements and Auger electron spectroscopy (AES) were used to examine the purity of the surfaces of platinum films evaporated onto two silicon-containing substrates, namely quartz and Pyrex glass. Abnormally low work function values were found for films evaporated onto a quartz substrate. The AES results indicate that the surface of the platinum film is contaminated by silicon and oxygen, most probably in the form of SiO groups. Heating of a quartz specimen in the vacuum chamber may also result in this contamination. No indication of any contamination was found when a Pyrex glass substrate was used. The possible processes that are responsible for the silicon and oxygen contamination are discussed. The relevance of the results to heterogeneous catalysis are discussed.