Field electron emission from amorphous carbon films grown in pure methane plasma

By using RF plasma-enhanced chemical vapor deposition, amorphous carbon films were grown in pure methane plasma. Field emission of the films were examined as a function of substrate temperature. It was found that the emission current from the samples prepared at substrate temperatures higher than 600 °C were considerably improved. According to the results by Raman spectroscopy, growth of graphite crystallites were promoted with high substrate temperatures. Moreover, the surface morphology was abruptly changed at high substrate temperatures over 600 °C. We discuss the field emission characteristics of the amorphous carbon films with regard to the structural features and the surface morphology.