MoO3 Modification Layer to Enhance Performance of Pentacene-OTFTs With Various Low-Cost Metals as Source/Drain Electrodes

Three groups of top-contact pentacene organic thin-film transistors (OTFTs) are fabricated with various low-cost metals (Ag, Al, and Cu) as source/drain electrodes. Different thick MoO₃ modification layers are inserted between pentacene and metals to optimize the device performance. The evolution of the device performance with the thickness of MoO₃ modification layer is independent of the type of metal. The optimized MoO₃ thickness of 10 nm is obtained in every group of OTFTs. The data simulation analysis demonstrates that the hole injection was dominated by thermionic emission mechanism at the interfaces of metals/pentacene, whereas the current transport was dominated by trap-limited space-charge-limited current carrier conduction mechanism with a proper thick MoO₃ modification layer between metals and pentacene, indicating that MoO₃ can significantly enhance the injection ability of holes, which is the origin of the device performance improvements in OTFTs with MoO₃ modification layer.