INFLUENCE OF THERMAL AND PLASMA TREATMENTS ON THE ELECTRICAL-PROPERTIES OF POLY(PARA-PHENYLENE VINYLENE)-BASED DIODES

We have studied the influence of plasma and thermal treatments on the electrical properties of poly(para-phenylene vinylene) (PPV) thin film s in metal-polymer-metal structures. Thermal heating of the samples mo difies the diode characteristic by reducing the voltage threshold and by favouring the formation of the rectifying contact at the bottom sid e. Plasma treatments with oxygen or nitrogen drastically change the co nductivity of the polymer with disappearance of the rectifying behavio ur and increase the current by many orders of magnitude. Attempts to e xplain the modifications of the electrical property of the treated sam ples are given, using previous results from X-ray photoelectron spectr oscopy (XPS) which highlight the role of the interfacial layer formed by chemical reaction between the polymer and metallic electrode.