The field emission microscope has been used to investigate the coadsorption of cesium and oxygen on retractory metals.
The minimum work function value was 1. 33 eV for the coadsorption layer on tungsten, which was formed by deposition of cesium on tungsten covered with oxygen, in comparison with 1.45 eV for cesium on clean tungsten. For rhenium, the minimum work function value was 1. 25 eV for the coadsorption layer, in comparison with 1.40 eV for cesium on clean surface.
In the case of adsorption of oxygen on tungsten and rhenium covered with cesium sufficiently, the temperature at which the activation phenomena occured was above 800°K for tungsten (O-Cs : W) but slightly higher temperature for rhenium (O - Cs : Re).
With increasing the oxygen coverage, the field intensity and the temperature at which the build-up phenomena occur increased.
The activation energy for both surface migration and thermal desorption of cesium increased with the oxygen coverage.
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