Confinement of nonequilibrium plasmas in microcavities with diamond or circular cross sections: Sealed arrays of Al/Al{sub 2}O{sub 3}/glass microplasma devices with radiating areas above 20 cm{sup 2}
- Laboratory for Optical Physics and Engineering, Department of Electrical and Computer Engineering, University of Illinois, 1406 W. Green St., Urbana, Illinois 61801 (United States)
Arrays of Al/Al{sub 2}O{sub 3}/glass microplasma devices with microcavities having diamond or circular cross-sectional geometries and radiating (active) areas >20 cm{sup 2} have been operated sealed-off in Ne, Ar, and Ar/D{sub 2} gas mixtures. Microcavities are fabricated in only one of the two electrodes, and the thickness of the completed package is {approx}170 {mu}m (excluding the quartz output window). Excited by a sinusoidal 20 kHz voltage wave form, arrays with active areas of 4.5x3 cm{sup 2} exhibit ignition voltages as low as 110{+-}5 V rms for Ne pressures of 400-700 Torr. Mixtures of 1% D{sub 2} in Ar at a total pressure of 300 Torr produce wavelength-integrated ({lambda}{approx}250-400 nm) intensities of {approx}1 mW cm{sup -2} over a 25 cm{sup 2} area. Optical micrographs show the operation of the microplasmas in two well-defined modes. For current densities below a threshold value ({approx}53 mA cm{sup -2} for 250 {mu}m dia. cavities and p{sub Ne}=400 Torr), diffuse uniform plasma is produced in each cavity but, with higher currents, a positive column having near-cylindrical geometry appears, as evidenced by the generation of intense emission localized in the region of weak electric field gradient near the axis of symmetry.
- OSTI ID:
- 20880104
- Journal Information:
- Applied Physics Letters, Vol. 89, Issue 22; Other Information: DOI: 10.1063/1.2393024; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
- Country of Publication:
- United States
- Language:
- English
Similar Records
Two-dimensional simulation of ac-driven microplasmas confined to 100-300 {mu}m diameter cylindrical microcavities in dielectric barrier devices
Self-pulsing 10{sup 4} A cm{sup -2} current density discharges in dielectric barrier Al/Al{sub 2}O{sub 3} microplasma devices