 Despite of the same functional dependence of the current density upon the electric field intensity, one could differentiate between Poole-Frenkel conduction upon Schottky conduction as they would result in straight lines with different slopes in a Poole-Frenkel plot.The theoretical slopes can be evaluated knowing the high frequency dielectric constant of the material (formula_25, where formula_26 is the vacuum permittivity), and confronting these with the slopes detected experimentally.As an alternative, one can evaluate the value for formula_27 equating the theoretical slopes to the experimental detected ones, provided that it is known if the conductivity is electrode-limited or bulk-limited.