Decay kinetics of luminescence and electron emission from MgO crystal powders in ac plasma display panels

Decay kinetics of luminescence at 5.2 eV and those of sustained electron emission from MgO crystal powders were investigated in order to understand the mechanism of discharge delay in ac plasma display panels and sustained electron emission from insulator. The decay of UV-luminescence was nonexponential and the decay was enhanced by increasing the temperature after showing negligible temperature dependence at low temperature. Existence of carrier traps was indicated by thermoluminescence measurements. As a possible mechanism, luminescence from a donor-acceptor pair in combination with thermal activation from carrier traps was introduced. The electron emission properties were evaluated by the measurement of statistical discharge delay time in ac plasma display panels as an indicator. By coating MgO crystal powders on the MgO protective film, the intensity of electron emission increased and its time and temperature dependence was reduced. A comparison under the same excitation revealed that the decay of UV-luminescence was steeper than that of electron emission. To explain the experimental data, we proposed the involvement of direct electron emission from electron traps synchronized with measuring voltages in addition to luminescence-associated electron emission. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3140605]