Synthesis of Carbon Materials Using Abnormal DC Glow Discharge Plasma CVD

Diamond is a valuable material for the industry because of useful properties including extreme hardness, wide-band optical transparency, and high thermal conductivity. Especially thick and large-scale diamond films can be used in various industrial applications. However, its practical use has been limited due its relatively high cost and scarcity. Microwave plasma CVD using 915MHz is one of the most commonly used methods for synthesizing diamond films. Recently, the plasma transition state from glow discharge to arc discharge has been used for the synthesis of diamond. This system has a greater potential for upward scalability because of its multiple cathode structure. The abnormal glow discharge plasma has the additional advantage of requiring only a very simple plasma generation system using direct current supply units, which results in a lower equipment cost. In the present study, we report the relationship between the obtained carbon materials and the results of optical emission spectroscopy (OES), including images of the first atomic hydrogen Balmer line and the C2(0,0) Swan band.