The use of inductively coupled plasma mass spectrometry to provide an absolute measurement of surface coverage, and comparison with the quartz crystal microbalance

It is often difficult to obtain an absolute measure of the quantity of an ultrathin layer of an element deposited onto a dissimilar solid surface, even though this is an important parameter for many surface studies. Auger and X-ray photoelectron spectroscopies provide only a relative measure of the quantity of a deposit, and nuclear or ion-scattering spectroscopies are limited in the adsorbatersubstrate pairs that can be measured and often require expensive accelerators that are not readily available. Inductively-coupled-plasma mass spectroscopy ICPMS.has been used as an ex-situ method to determine the absolute coverage at sub-monolayer levels in semiconductor process control. However, it does not seem to have been used to date for determining surface coverage of adsorbates for other surface-science applications, even though it can do this routinely with an accuracy of few percent. This paper uses ICPMS to determine the coverage of a sub-monolayer of antimony on gold, and shows that the results are consistent with high-precision measurements taken with a quartz crystal microbalance on the same sample. q1999 Elsevier Science B.V. All rights reserved