The effect of electric field on adsorbed layers of cesium on various refractory metals

• Published in: Surface science 1964, Vol.2, p.177-187
• Main Authors: Swanson, L.W, Strayer, R.W, Charbonnier, F.M
• Format: Article
• Language: English
• ISSN: 0039-6028; 1879-2758
• DOI: 10.1016/0039-6028(64)90056-1

A study of the effect of high positive and negative electric fields on surface diffusion, thermodynamic equilibrium coverage and thermal desorption of cesium on tungsten and molybdenum has been accomplished by means of field emission microscopy. The results show field dependent variations of both the pre-exponential factor and activation energy of the surface diffusion coefficient written as D = D 0 exp (− E d F / kT). At temperatures sufficient to induce mobility, an increase or decrease in cesium coverage in the high field region of the emitter occurs with positive or negative fields respectively. Thermal desorption rates are not greatly affected by negative fields; positive fields, on the other hand, produce large variations in desorption rates due to field desorption. Most of the field effects can be analyzed in terms of μ F and 1 2 αF 2 interactions except for field desorption which involve more complex field interactions.