Poole-Frenkel conduction and the neutral trap

The potential φ of a neutral trap may, in approximation, be represented by an inverse power law φ ∝ r-n, where r is the distance and n varies from 1 to ∞. The field lowering of the potential barrier is then proportional to Em. E is the field and m=0.5 for n=1 and m→1 for n→∞. This lowering may explain high-field conduction results in which the logarithm of the current density was found to be proportional to Em.