Arrays comprising 250 000 Si microcavity plasma devices, each with an emitting aperture of 50×50 μ m2 and tapered sidewalls (inverted pyramid cavity), have been fabricated in 100-mm (4″) diam. wafers and operated in the rare gases and Ar N2 mixtures with sinusoidal ac or bipolar dc excitation. Having an overall active area of 25 cm2 and a 25% filling factor, these 500×500 arrays exhibit the pixel-to-pixel emission uniformity characteristics of arrays at least a factor of 6 smaller, and yet are efficient in generating vacuum ultraviolet (VUV) radiation. Luminous efficacies above 6 lmW and luminance values approaching 2000 cd m2 are measured when a 500×500 array, operating with a Ne/50% Xe gas mixture, illuminates a 20-μm -thick film of a commercial green phosphor (Mn: Zn2 Si O4). Despite the nonoptimal transmission geometry of the array-phosphor structure, the efficacy and luminance produced by the VUV-driven phosphor for a Ne/50% Xe mixture and a total pressure of 800 Torr are measured to be 7.2±0.6 lmWatt and 525±75 cd m2, respectively, for a 20-kHz sinusoidal ac voltage of ∼284 V rms. Maximizing the luminous efficacy-luminance product lowers the optimal pressure of Ne/50% Xe mixtures to roughly 1 atm. The magnitude of the radiant output generated by these arrays, in addition to the rapid rise in emitting efficiency with increased Xe content in Ne/10%-50% Xe mixtures, suggest that this microplasma array structure will be of value for both microdisplay and biomedical applications.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)