Field-emission flicker noise from potassium adsorbed on W(111) bounded and unbounded surface diffusion by spectral analysis

The spectral density functionsW(f) of the field-emission flicker noise of potassium adsorbed on the tungsten (111) region were determined. The analysis in terms of the Gesley-Swanson or the Timm and Van der Ziel model gives surface diffusion energies between 0.54 and 0.31 eV for (average) coverages from 0.15 to 0.38 and diffusion prefactors between 3×10^–1 and 10^–4 cm²/s. The fitting procedures are successful for both bounded and unbounded diffusion though in opposite order of temperature, as expected.On leave from Wrocaw University