Alignment-free process for asymmetric contact electrodes and their application in light-emitting organic field-effect transistors

We developed an alignment-free process for asymmetric contacts of Au and Al and applied it to light-emitting organic field-effect transistors. Because electrons were injected efficiently from Al contacts, the emission intensity and onset voltages for light were significantly better than those in a device with conventional Au/Cr contacts. Moreover, a device with 1 mu m channel length asymmetric contacts of Au and Al showed about 50 times higher current than that of the device with conventional Au/Cr contacts. This significant improvement can be ascribed to both dual space-charge formation of holes and electrons and low carrier injection barriers. (c) 2008 American Institute of Physics.