Porous carbon film electrodes prepared by pulsed discharge plasma CVD

Abstract

Carbon films having porous structure were deposited by means of the pulsed discharge (PD) plasma chemical vapour deposition (CVD) method, where the plasma was generated by the PD in a H 2–C 2H 2 gas mixture at about 50 Torr of total pressure, with a substrate of Al located near the plasma. A Co–Fe composite film synthesized from Cobalt Nitrate Hexahydrate and Iron Nitrate Enneahydrate was deposited on the substrate surface and used as the catalyst to form the porous structure. Frequency and duty ratio of the pulsed discharge were 800 Hz and 20%, respectively. The deposition time was 10 min and the substrate temperature was about 210 °C. Many pores and fibrous structures were observed by SEM. Small grains of about 0.05 µm in size were observed by transmission electron microscopy (TEM). A graphite like structure was observed in the small grains via high resolution TEM. Raman spectrum of the film showed two broad peaks known as D and G peak at around 1350 and 1600 cm − 1 . The capacitance and resistance of the films, calculated from transient of current after DC pulse voltage was applied, were 32 µF/cm 2 and 315 Ω/cm 2, respectively.