THIN POLYMER-FILMS ON METAL - ASSESSMENT OF A CONDUCTIVITY MECHANISM VIA VALENCE-BAND SPECTRA

When prepared as very thin layers on a conducting substrate, organic a nd polymer films are generally not prone to the charging effect when s tudied for example with XPS, HREELS or STM. For Langmuir-Blodgett laye rs of Arachic Acid, Behenic Acid, and Polyvinylstearate, it is shown t hat XPS valence band spectra exhibit an increased density of states ju st below the Fermi level. It is suggested that this effect is due to a n electronic interaction with the substrate, allowing for electrical c onductivity in the adsorbate layer.