Photoelectron emission from FAB-treated polyethylene film

We have reported that the threshold energy for photoelectron emission varied with the electronic surface current for the inorganic material, e.g. Muscovite mica or SiO₂ film on Si wafer. For the mica specimen, the surface current changes from ionic current to electronic current by the fast atom bombardment (FAB) treatment, and the electronic surface current has an effect on photoelectron emission. For the farther study of the surface properties of solid dielectrics, we have investigated about the photoelectron emission and surface conduction phenomenon for polyethylene film treated by FAB. The threshold energy of photoelectron emission increases with the decreasing of the light intensity. This shift in photothreshold is thought to correspond to the so-called quasi-Fermi level in the surface of polyethylene same as the case of mica. On the other hand, the threshold energy does not change with respect to the FAB treatment. The increase in surface current according to the increasing of relative humidity was observed. This shows that the surface current for polyethylene is ionic even for the FAB treated specimen different from the case of mica specimens. We discuss about the relationship between such phenomena and surface condition for polyethylene in comparison with inorganic material.