Improved Performance of Pentacene Organic Field-Effect Transistors by Inserting a V 2 O 5 Metal Oxide Layer

We fabricate pentacene-based organic field effect transistors (OFETs), inserting a transition metal oxide (V2O5) layer between the pentacene and Al source-drain (S/D) electrodes. The performance of the devices with V2O5/Al S/D electrodes is considerably improved compared to the pentacene-based OFET with only Al S/D electrodes. After the 10-nm V2O5 layer modification, the effective field-effect mobility of the devices increases from 2.7 × 10−3 cm2 /V·s to 8.93× 10−1 cm2/V·s. Owing to the change of the injection property, the effective threshold voltage (Vth) is changed from −7.5 V to −5 V and the on/off ratio shifts from 102 to 104. Moreover, the dispersion of sub-threshold current in the devices disappears. These performance improvements are ascribed to the low carrier injection barrier and the reduction of contact resistance. It is indicated that V2O5 layer modification is an effective approach to improve pentacene-based OFET performance.