Synthesis of electro-active manganese oxide thin films by plasma enhanced chemical vapor deposition

The good stability, cyclability and high specific capacitance of manganese oxide (MnOx) has recently promoted a growing interest in utilizing MnOx in asymmetric supercapacitor electrodes. Several literature reports have indicated that thin film geometries of MnOx provide specific capacitances that are much higher than bulk MnOx powders. Plasma enhanced chemical vapor deposition (PECVD) is a versatile technique for the production of metal oxide thin films with high purity and controllable thickness. In this work, MnOx thin films deposited by PECVD from a methylcyclopentadienyl manganese tricarbonyl precursor are presented and the effect of processing conditions on the quality of MnOx films is described. The film purity and oxidation state of the MnOx films were studied by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Preliminary electrochemical testing of MnOx films deposited on carbon fiber electrodes in aqueous electrolytes indicates that the PECVD synthesized films are electrochemically active.