Nanoporous alumina as a dielectric for microcavity plasma devices: Multilayer Al/Al2O3 structures

摘要: Nanostructured Al2O3 films with mean pore diameters of 20 nm, 5–30μm in thickness, and grown onto Al foil by a multiple step electrochemical process, provide dielectric having superior properties for microplasma devices arrays. Multilayer Al/nanoporous structures 100–300μm diameter (dia.) cylindrical microcavity an overall thickness ∼200μm are robust operate the abnormal glow mode Ne or Ar/2–5% N2 mixture gas pressures (300 K) 500–700 Torr. When driven sinusoidal ac waveform at frequencies 5–20 kHz, small arrays (3×3→10×10) 100μm dia. rms voltages currents ∼160–270V 0.4–4.5 mA, respectively. Arrays as large 10×10 have been fabricated to date generate azimuthally uniform discharges each pixel without need external ballast. For voltage ∼275V, 5×5 produce luminance 2700cdm−2 600 Torr excitation frequency kHz.