Interface formation of Ca with poly(p-phenylene vinylene)

We have investigated the interface formation of Ca with poly(p-phenylene vinylene) (PPV) using x-ray photoemission spectroscopy. The most significant part of our findings was the very late occurrence of band bending at the Ca/PPV interface and the lack of strong reaction between the Ca overlayer with the PPV substrate, indicating that the Schottky barrier formation in Ca/PPV was a slow process. The late barrier formation at the Ca/PPV interface may be due to the shielding by surface oxygen impurities, part of which underwent calcium oxide formation at the interface.