Conducting and ordered carbon films obtained by pyrolysis of covalently attached polyphenylene and polyanthracene layers on silicon substrates

Abstract

Graphite-like thin films with excellent electrode properties were obtained by pyrolysis of nanometer thick electrografted layers of polyphenylene and polyanthracene layers on silicon substrates in a forming gas atmosphere. The pyrolyzed grafted films, characterized by using different surface analytical techniques such as ellipsometry, cyclic voltammetry, Raman spectroscopy, X-ray photo-electron spectroscopy, atomic force microscopy, and transmission electron microscopy, consist of graphite-like layers of ∼6 nm crystallite thickness with electrochemical properties that are similar to those of pyrolyzed photoresist films. Hence, pyrolysis of covalently bonded organic layers is an alternative approach to obtain very thin conducting carbon films strongly attached to a substrate. Furthermore, this technique can be applied to substrates of any geometrical structure, in contrast to spin coating techniques. It is suggested that thin graphite-like films on silicon produced in this manner could serve as substrate for spectroelectrochemical investigations of surface reactions by attenuated total reflectance experiment or in the production of optically transparent electrodes.