A common gate thin film transistor on poly(ethylene naphthalate) foil using step-and-flash imprint lithography

In this paper the fabrication of flexible thin film transistors (TFTs) on poly(ethylene naphthalate) foil is reported, with the source–drain layer patterned by step-and-flash imprint lithography (SFIL) as a first step towards fully UV-imprinted TFTs. The semiconductor was deposited by inkjet printing of a blend of TIPS-pentacene/polystyrene. The bottom contact, bottom gate TFTs were fabricated with the foil reversibly glued to a carrier, enhancing the dimensional stability and flatness of the foil to result in a thinner and more homogeneously distributed residual layer thickness. The obtained performance of the TFT devices, showing a mobility of μ = 0.56 cm2 V−1 s−1 with an on/off ratio of >107 and near-zero threshold voltage, was found to be in good agreement with similar, photolithographically patterned state-of-the-art devices recently reported in literature. The results presented here show the feasibility of SFIL as a roll-to-roll compatible and down scalable patterning technique on flexible PEN foil for the fabrication of bottom-gate, bottom-contact flexible high-quality TFTs.