An a.c. retarding potential technique for the continuous measurement of changes in work function

Abstract

An a.c. technique is described for the measurement of work function changes which can be performed in any system with a suitable low energy electron gun. It is especially compatible with LEED/Auger or cylindrical mirror analysis (CMA)/Auger systems, is capable of 1 meV resolution, has a fast response time and good reproducibility. Unlike the Kelvin technique, a stable reference surface is not required. The absence of a reference permits a more reliable estimate of gas exposure at the surface under investigation and also allows continuous measurements of work function change during vapour deposition experiments. The method does not suffer from the drift problems. The technique has been applied to the adsorption of ethylene on W(100) and has been compared with the Kelvin technique.