One quarter million (500x500) pixel arrays of silicon microcavity plasma devices: Luminous efficacy above 6 lumens/watt with Ne/50% Xe mixtures and a green phosphor

Arrays comprising 250 000 Si microcavity plasma devices, each with an emitting aperture of 50x50 mu m(2) and tapered sidewalls (inverted pyramid cavity), have been fabricated in 100-mm (4(')) diam. wafers and operated in the rare gases and Ar/N-2 mixtures with sinusoidal ac or bipolar dc excitation. Having an overall active area of 25 cm(2) and a 25% filling factor, these 500x500 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 lm/W and luminance values approaching 2000 cd/m(2) are measured when a 500x500 array, operating with a Ne/50% Xe gas mixture, illuminates a 20-mu m-thick film of a commercial green phosphor (Mn:Zn2SiO4). 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 lm/Watt and 525 +/- 75 cd/m(2), respectively, for a 20-kHz sinusoidal ac voltage of similar to 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. (c) 2006 American Institute of Physics.