Characteristics of conjugated hydrocarbon based thin film transistor with ionic liquid gate dielectric

Thin film transistors (TFTs) with ionic liquid gate dielectrics, [1-ethyl-3-methylimidazolium][bis(trifluoromethanesulfonyl)imide] (emim[TFSI]) and [1-butyl-3-methylimidazolium][hexafluorophosphate] (bmim[PF6]), are fabricated with thin films of one dimensional (1D) hydrocarbon, [7]phenacene. P-channel characteristics are observed for [7]phenacene TFTs with both ionic liquids by use of platinum electrode. The field-effect mobility μ for [7]phenacene TFT with bmim[PF6] was recorded to be 0.28 cm2 V−1 s−1. The value of absolute threshold voltage, |VTH|, was less than 2.5 V, showing low-voltage operation. The accumulation of hole in the [7]phenacene TFTs with ionic liquids was confirmed from the voltage or time dependence of capacitance in metal–insulator-semiconductor structure, which shows that these TFTs operate electrochemically and the carriers are accumulated in the whole of [7]phenacene thin films.

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► We made aromatic hydrocarbon ([7]phenacene) electrochemical transistor with ionic liquids.
► Low voltage operation and high field-effect mobility was realized in [7]phenacene electrochemical transistor.
► Availability of bmim[PF6] gel for electrochemical transitor was shown.
► Future prospective is shown for application of aromatic hydrocarbon electrochemical transistor.