 However, the conductivity arising from the Poole-Frenkel effect is detected in presence of bulk-limited conduction (when the limiting conduction process occurs in the bulk of a material), while the Schottky current is observed when the conductivity is contact-limited (when the limiting conduction mechanism occurs at the metal-insulator interface).The electrical conductivity formula_1 of dielectrics and semiconductors in presence of high electric fields (more than formula_2 for insulators and over formula_3 for semiconductors) increases approximately as described by the Poole's law (eventually leading to electrical breakdown)