Use of bilayer gate insulator to increase the electrical performance of pentacene based transistor

•Bottom-gate top-contact pentacene-OFETs have been fabricated with low-cost organic/inorganic bilayer gate dielectrics.•The effect of bilayer gate insulator on the electrical performance of pentacene-based OFET has been investigated.•The obtained highest mobility and on/off ratio values belong to OFET3 having PVP/Al2O3 bilayer insulating material.

In this study, bottom-gate top-contact pentacene-based organic field effect transistors (OFET) with various spin-coated ultrathin organic dielectrics on anodized aluminum oxide (Al2O3) bilayer gate dielectrics were fabricated. We have investigated the influence of the bilayer gate insulator having different combinations on the OFETs performance. Polystyrene (PS), poly-4-methylstyrene (P4MS), Poly-4-vinylphenol (PVP), poly-methylmethacrylate (PMMA) and Poly(4-vinylphenol-co-methyl methacrylate) (PVP_co_PMMA) were used as an organic dielectric. The results indicate that Al2O3 gate dielectric with Poly (4-vinylphenol) shows the optimum electrical performance with carrier mobility as large as 0.65 cm2/Vs, on/off current ratio of 106, and threshold voltage as −3.8 V.