The activation energy for the surface self-diffusion of epitaxial Er crystals, grown on a W field emitter tip, was determined. The values of the activation energy which were calculated from Arrhenius plots, and the field emission patterns of epitaxial Er crystals, were presented. The activation energy for surface self-diffusion appeared to be markedly anisotropic (table 114). Two different values were obtained for two crystallographically different surfaces of the crystals. The electric field considerably affected the process of surface diffusion. Evidence for probable changes in the binding energy between Er atoms during the build-up was found. These changes could influence the results of’ measurements, of the activation energy for surface self-diffusion, when no field was applied. It was expected that the error caused by this effect was not much greater than the error arising from the method of measurement.

G.Kozlowski, A.Ciszewski, W.Swiech: Journal de Physique – Colloque C2, 1986, 47[3], 337-40

Table 114

Er Diffusion on Er Crystal Surfaces