Pool-Frenkel effect and high frequency dielectric constant determination of semiconducting P(2)O(5)-Li(2)MoO(4)-Li(2)O and P(2)O(5)-Na(2)MoO(4)-Na(2)O bulk glasses

The ternary 70P(2)O(5)-10Li(2)MoO(4)-20Li(2)O and 70P(2)O(5)-10Na(2)MoO(4)-20Na(2)O glasses, prepared by the press-melt quenching technique, were studied at temperatures between 298 and 418 K for their high dc electric field properties. For the above purpose, the effect of a strong electric field on the dc conduction of these amorphous bulk samples was investigated using the gap-type electrode configuration. At low electric fields, the current-voltage (I - V) characteristics have a linear shape, while at high electric fields (> 10(3) V/cm), bulk samples show nonlinear effects (nonohmic conduction). Current-voltage curves show increasing departure from Ohm's law with increasing current density, leading to critical phenomena at a maximum voltage (threshold voltage), known as switching (switch from a low-conduction state to a higher-conduction state at threshold voltage). The Pool-Frenkel high-field effect was observed at electrical fields of about 10(3)-10(4) V/cm; then the lowering factor of the potential barrier, the high frequency dielectric constant, and the refractive index of these glasses were determined.