STUDIES OF THE POLYMER-METAL INTERFACE IN METAL-PPV-METAL DEVICES

We report the results obtained from electrical measurements and surfac e analysis by photoelectron spectroscopy (XPS) performed in polyparaph enylene-vinylene (PPV) thin films sandwiched between metallic electrod es. Current-voltage characteristics of metal-polymer-metal devices are dissymetrical with rectifying contacts at top electrodes (Cr or Al) a nd blocking one at bottom electrodes (Cr). Analysis of the core level spectra of carbon, oxygen and metals in the interfacial layers leads t o the conclusion that the rectifying behaviour of polymer-metal contac t is in close relation with the formation of metallic oxide-carbon com plexes at the interfaces.