Diamond synthesis by plasma jet above a liquid surface

A new approach was proposed for the low-pressure diamond synthesis on high-resistant substrates using liquids as starting materials for carbon sources. The principle is to generate a DC plasma between the copper nozzle and the negatively-biased liquid surface under reduced pressure. The discharge continued with an applied voltage between 1.5 and 2 kV and at pressures between 30 and 50 kPa using a mixture of water– ethylene glycol solution. Plasma thus generated was led onto the silicon substrate placed horizontally and 1 mm over the nozzle top. The deposits distributed almost concentrically centered at the point directly above the nozzle axis. After deposition for 1 h, well-faceted diamond was formed in a limited region. The growth rate of the diamond film was 10 μm/h.