Photoemission-induced Atmospheric-Pressure DC Gas Discharge Using Back-Illuminated Nano Thickness Photocathode

Photoemission-induced atmospheric-pressure DC gas discharge was successfully generated using a 9 nm gold thin-film deposited on quartz glass as a photocathode which was back-illuminated with UV light at wavelengths of 172 nm (Xe excimer lamp), 254 nm (Hg lamp), and 265 nm (Deep UV-LED). A stable discharge current of more than 30 mu A at 1450 V in Ar and 50 mu A at 4000 V in air was achieved by using 172 nm while it was limited by the power densities and quantum efficiencies of other UV sources. The optical emission spectroscopy showed emissions from excited species in both Ar and air plasma.