Electrical Properties of Lead Phthalocyanine Films

Current density-voltage characteristics have been obtained from thin films of lead phthalocyanine particles dispersed in a polymer binder when sandwiched between ohmic gold and blocking aluminium electrodes. At low voltages, the current in the forward direction shows Schottky diode behaviour. The diode parameters are evaluated using the model of Cheung and Cheung. Barrier heights and widths are determined as a function of applied voltage. A number of parameters is evaluated on the basis of the theory of space-charge-limited conduction, and the following values are obtained: p$\text{}_{0}$ = 8.5 × 10$\text{}^{18}$ m$\text{}^{-3}$, concentration of the traps per unit energy range at the valence band P$\text{}_{0}$ ≈ 2.5 × 10$\text{}^{44}$ J$\text{}^{-1}$m$\text{}^{-3}$, temperature parameter of trapping distribution T$\text{}_{c}$ ≈ 500 K and total trapping concentration, N$\text{}_{t}$ ≈ 1.7 × 10$\text{}^{24}$ m$\text{}^{-3}$.