Improved Performance of Pentacene Organic Field-Effect Transistors by Inserting a V₂O₅ 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 (V_th) 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.