Secondary electron emission coefficients in plasma display panels as determined by particle and fluid simulations

The secondary electron emission coefficient (gamma(se)) of ions and excited species in a plasma display panel (PDP) was studied by means of 2-dimensional fluid and 1-dimensional particle-in-cell Monte Carlo collision simulations. Relations between the driving voltage and the luminous efficiency observed in experiments are reproduced at low and high Xe concentrations. Agreement between experiments and simulations, however, requires careful selection of the gamma(se) of ions and excited species. The trend of the efficiency as a function of the driving voltage is particularly sensitive to the gamma(se) of Xe excited species. For the conditions typically encountered in PDP cells (pd= 1-10 Torr cm), the dependence of the gamma(se) on the energy of impinging ions can be neglected in discharges of pure gases. This is a consequence of multiple charge exchange collisions in the cathode region. In Xe-Ne mixtures, however, the ion energy distribution function on the cathode depends on the mixture ratio. Typically more energetic ions can reach the cathode in gas mixtures and the gamma(se) is enhanced.