Carbon nanotube generated electron beam produced plasmas

Abstract

A device using an energetic electron beam from a carbon nanotube electron emitter has been developed to generate plasmas at pressures near or below atmospheric. The low-pressure electron source region (10−6 mbar) and the higher pressure (up to 1 atmosphere) plasma generation region are separated by a 300 nm SiNx window/membrane. The energy of the electron beam is of the order of 10 kV with a current of 10 μA prior to passing through the window, with nearly 85% of the beam passing through the window to the plasma generation region with a 10% loss in energy. The device could be operated in one of two modes, closed or opened. Closed mode operation has been used to generate excimer emissions from XeI* and XeCl* at 253 nm and 308 nm, respectively, at pressures below atmospheric. Ambient air has been used in the open mode operation with and without a flow of argon or helium across the SiNx window. Optical emission spectroscopy revealed that the open mode operation yielded a variation of excited state species that was found to be dependent on the electron beam energy and the neutral gas flow in the reaction region.