Electrical characterization of Fermi level pinning in metal/3,4,9,10 perylenetetracarboxylic dianhydride interfaces

摘要

Systematic studies of current injection from different metal electrodes to metal/3,4,9,10 perylenetetracarboxylic dianhydride (PTCDA) interfaces have been carried out. It has been observed that the barrier for carrier injection cannot be explained by simple vacuum alignment scheme. Moreover, injection barrier is almost independent of metal work function. These observations are explained by the changes of barrier height due to interface dipole barrier which compensate for the difference of work function of PTCDA and metals, leading to metal independent injection barrier and Fermi level pinning at metal/PTCDA interfaces.