SCHOTTKY-BARRIER FORMATION AND ELECTRICAL TRANSPORT IN OXYGEN-DOPED TRICLINIC LEAD PHTHALOCYANINE FILMS

The electrical properties of oxygen-doped thin films of triclinic lead phthalocyanine with mixed (Al, Au) electrodes are studied. Au-PbPc-Al and Al-PbPc-Au structures show different behaviour due to the varying oxygen distributions in the PbPc and the existence of an interfacial aluminium oxide layer in the latter case. At low voltages both types of device show Schottky diode behaviour. For Au-PbPc-Al structures the model of Cheung and Cheung is used to derive diode parameters. Barrier heights and widths are determined as a function of applied voltage and trap densities, hole concentrations, and the temperature parameter of the trapping are found to be consistent with reported values. The present results emphasise the role of oxygen doping and interfacial oxide layers in determination of the electrical behaviour of PbPc based devices.