Coadsorption of Ba and O on polycrystalline W

The thin film properties of the barium-oxygen-tungsten system were studied using a combination of AES, Δφ, and low-damage SIMS techniques. Due to the extreme reactivity of barium toward residual gases, all experiments not requiring oxidation (including simultaneous SIMS and barium deposition) were completed at operating pressures never exceeding the 10^-11 Torr range. The barium-oxygen-tungsten system was found to have work function-coverage properties similar to those of the cesium-oxygen-tungsten system. The order of adsorption was found to give different structures; and in the case of Ba → O/W, a patchy surface was discovered. The low-damage SIMS yields showed correlation with work function.