ELLIPSOMETRY-LEED STUDY OF ADSORPTION OF OXYGEN ON (011) TUNGSTEN

The direct combination of ellipsometry and low-energy-electron diffraction (LEED) techniques has been extended to a study of room temperature oxygen adsorption on (011) tungsten. It is shown that, by use of a special continuous data-taking method, ellipsometry is easily capable of detecting small fractions of a monolayer of adsorbed oxygen on this metal crystal face. From the partial correlation of LEED and ellipsometry data, average sticking probability for oxygen adsorption in the first 1 2 monolayer of atoms is deduced to be 0.2 or 0.4, depending on the choice of adsorption model. The experimental ellipsometry results are not understandable in detail in terms of existing ellipsometry theory. However, in view of the LEED results, it is tentatively concluded that the present results support a previously published complicated adsorption model involving oxygen atom-tungsten atom rearrangements. © 1969.