Radio-frequency microdischarge arrays for large-area cold atmospheric plasma generation

By flowing gases through arrays of microhollow cathode holes, large area (12 mm in diameter) uniform and stable discharges could be generated by a rf power supply. Both the rf power and the gas flow through the cathode holes played key roles in maintaining uniform and stable discharges. The discharges could be stable for a period longer than one hour in pure helium (He) and in He containing 1% hexamethyldisiloxane (HMDSO). By using a third steel electrode biased with a pulse power supply (100 kHz, 50% duty cycle), the plasma from arrays of cathode holes could be extended to 20 mm in length. Amorphous carbon films deposited by the extended atmospheric plasma using 1% HMDSO/He reactants exhibited the same structure as those by low pressure plasma chemical vapor deposition.