Conduction in Thin Polymer Films

Thin polymer films have been made from a variety of starting monomers and their electrical conduction has been studied. The films are produced both by ultraviolet surface photolysis and by a cold-cathode glow-discharge technique. The samples are made in the form of a capacitor sandwich on a glass substrate with aluminium electrodes. The whole sample is made in a high-vacuum system, without breaking vacuum, using out-of-contact masking techniques. Generally, depending on the starting monomer, the polymer films are "short"-free down to a thickness of about 100 angstrom, and electric fields up to 10(7) V/cm may be sustained. The current/voltage characteristics of the films have been investigated as a function of temperature and thickness. One theory to account for the conduction in these materials is presented and compared with other approaches to the problem.