Patent ID: 7923721

Claim:
An organic thin film transistor comprising: a substrate; a gate electrode placed on the substrate; a gate insulating film placed on the gate electrode and the substrate; a source electrode and a drain electrode which are placed on the gate insulating film and the substrate; a first organic semiconductor layer of a first conductivity type placed on the gate insulating film between and directly on the source electrode and the drain electrode; a second organic semiconductor layer of a first conductivity type placed on the first organic semiconductor layer; a third organic semiconductor layer of a second conductivity type placed on the second organic semiconductor layer; and an electrically floating conductor layer placed directly on the third organic semiconductor layer, wherein the third organic semiconductor layer and the second organic semiconductor layer define a p-n diode sandwiched by the first organic semiconductor layer and the conductor layer, and the p-n diode being configured to prevent a short circuit through the conductor layer between the source electrode and the drain electrode.