Space-Charge-Limited Currents in Copper Phthalocyanine Thin Films

Abstract

Measurements of space-charge-limited currents have been made on evaporated thin films of the compound copper phthalocyanine using Ohmic contacts. A complete study of the current as a function of voltage, temperature, thickness, and illumination indicates that all the results are consistent with the assumption of an exponential distribution of trapping states of the form Nt(E) = kTcP0 exp (E/kTc), where kTcP0 is a parameter related to the total trap density. Practical techniques for obtaining values for the mobility, density of states, total trap density, trap distribution in the vicinity of the Fermi level, and trap capture cross section are outlined and values reported.