Diamond film deposition from ethylene glycol/water solution using a dc-plasma jet method

A diamond film was deposited from a mixture of ethylene glycol and water using a dc−plasma jet method above liquid, in which the plasma was directly generated on a solution surface. Vaporized molecules from the surface were decomposed into radicals in the plasma. Optical emission spectroscopy revealed the presence of CO, OH, CH, C2 and H. The relative intensities of C2 to OH and CH increased with the ethylene glycol content. Diamond was deposited in the concentration range of ethylene glycol from 60 to 90 mol%. The 80 mol% concentration was the optimum value for diamond film deposition, whereas the lower concentration than 80 mol% resulted in an uncovered substrate at the center exposed to the jet. The typical growth rate of the diamond film was 10 μm/h. The crystalline film consisted of well faced particles less than 5 μm in size.