Thickness dependence of space charge limited current and injection limited current in organic molecular semiconductors

We report the experimental investigations on space charge limited current (SCLC) and injection limited current (ILC) in copper phthalocyanine (CuPc), sandwiched between two metal electrodes. Thickness dependence of current-voltage characteristics of SCLC and ILC is accurately reproduced by the electric field and temperature dependent charge carrier mobility, without invoking charge density dependent mobility. These results are interpreted using a consistent description of SCLC and ILC, based on a unified model of hopping transport within Gaussian density of states in CuPc.