Carbon nanotubes (CNT), fullerenes, nano-diamond and other nano-structured carbon (nC) materials attract a great interest because of their unique properties. In our recent publications it was shown that such nC thin film materilas maybe grown efficiently by chemical vapor deposition (CVD) from hydrogen-methane gas mixture activated by direct current (DC) discharge [1,2]. The better understanding of the nC species growth mechanism is necessary for optimization of CVD process and film properties. In this study we use on-situ diagnostics of DC discharge plasma by optical emission spectroscopy (OES) and current-voltage (I-V) characteristics drawing at varried gas mixtures and total gas pressures. The OES and I-V measurements were performed in combination with comprehensive study of the CVD film morphology, structure and other properties. The presence of spectral features corresponding to CH and C2 carbon species in CVD plasma allow us to propose the mechanism of nC material growth. The OES and I-V curves was used for optimization of our CVD process allowing to produce highly efficient nC cold cathodes applicable for various vacuum electronic devices.

[1] A.N. Obraztsov, A.P. Volkov, I. Pavlovsky, Diamond and Rel. Mat., 9(2000)1190.
[2] A.N. Obraztsov, I.Pavlovsky, A.P. Volkov et al., J. Vac. Sci. Technol. B, 18(2000)1059.