Observation of electron injection in an organic field-effect transistor with electroluminescence

A tetracene field-effect transistor (FET) with Au source and drain electrodes showed p-channel type behaviour, where the injected holes were the main carriers. Application of an ac electric field to the source electrode, while drain and gate electrodes were grounded, induced electroluminescence (EL) around the source electrode that was caused by alternating electron and hole injection. This result indicated that electron injection into tetracene was possible from a metal with a high work function such as Au. The application of an ac voltage superposed on a dc voltage showed that electron injection was assisted by the space-charge field that originated from holes accumulated around the source electrode.