A model is proposed for the observed hysteretic behavior of ac-coupled ZnS:Mn thin-film electroluminescent devices. The following mechanisms are invoked: (1) tunnel injection from ZnS-dielectric interfaces (ℰ4106 V/cm), (2) electron-hole pair generation, (3) deep trapping of holes, leading to space-charge formation, (4) charge storage at the ZnS-dielectric interfaces, and (5) direct recombination of injected electrons and trapped holes. When these mechanisms are combined in a self-consistent numerical simulation model, a bistability of charge transfer versus applied voltage is obtained which exhibits many of the characteristics of the observed device behavior. Experimental evidence in support of the individual assumptions is also discussed.

Apparent deviations from Paschen’s law, observed in ac plasma panels, have been resolved by generalizing the breakdown criterion to include the dependence of the secondary electron emission coefficient on E/p0. Incorporation of this dependence into the proposed effective coefficient involves consideration of both the back-diffusion phenomenon and the influence of E/p0 on the efficiency of metastable atom generation. Calculated voltage breakdown curves in pure neon and neon plus 0.1% argon mixture are in good agreement with experimental data for both the metal electrode dc discharges and the insulator-covered electrode discharges found in ac plasma panels.

The dynamics of a highpressure ac gas discharge between dielectric coated electrodes near breakdown threshold

A generalized expression has been derived for the effective secondary electron emission coefficient γ, in Penning mixtures which incorporates the effect of both the majority and minority ions. Specific calculations for ac panels having an Ne+0.1%Ar mixture show that even a relatively small value of γAr not only significantly lowers the breakdown voltages, but also moves the voltage minimum to higher p0d values and makes the right-hand side of the Paschen curve less steep. This sensitivity of the effective coefficient γ on γAr is sufficient to explain the critical dependence of the shape of the measured breakdown voltage curves in ac panels on minor changes in the surface properties of the deposited insulator surfaces.

Experimental results are presented for the influence of controlled levels of important reactive impurities (N,, O^, Hfi, COjj) on the aging characteristics of the operating voltages of ac plasma display panels. Details are also given of a novel method of modifying the electronic properties of MgO surfaces by discharge processing in an oxygen-doped Ne-0.1% Ar Penning mixture.