title: High performance p-type organic thin film transistors with an intrinsically photopatternable, ultrathin polymer dielectric layer.
abstract: A high-performing bottom-gate top-contact pentacene-based oTFT technology with an ultrathin (25-48 nm) and electrically dense photopatternable polymeric gate dielectric layer is reported. The photosensitive polymer poly((±)endo,exo-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid, diphenylester) (PNDPE) is patterned directly by UV-exposure (λ= 254 nm) at a dose typical for conventionally used negative photoresists without the need for any additional photoinitiator. The polymer itself undergoes a photo-Fries rearrangement reaction under UV illumination, which is accompanied by a selective cross-linking of the macromolecules, leading to a change in solubility in organic solvents. This crosslinking reaction and the negative photoresist behavior are investigated by means of sol-gel analysis. The resulting transistors show a field-effect mobility up to 0.8 cm2V-1s-1at an operation voltage as low as -4.5 V. The ultra-low subthreshold swing in the order of 0.1 V dec-1as well as the completely hysteresis-free transistor characteristics are indicating a very low interface trap density. It can be shown that the device performance is completely stable upon UV-irradiation and development according to a very robust chemical rearrangement. The excellent interface properties, the high stability and the small thickness make the PNDPE gate dielectric a promising candidate for fast organic electronic circuits.
authors.affiliation: Materials-Institute for Surface Technologies and Photonics, Franz-Pichler Straße 30, Weiz A-8160, Austria.
authors.forename: Andreas
authors.initials: A
authors.lastname: Petritz
authors.affiliation: Chemistry of Polymeric Materials, University of Leoben, Otto Glöckel-Straße 2, Leoben A-8700, Austria.
authors.forename: Archim
authors.initials: A
authors.lastname: Wolfberger
authors.affiliation: Materials-Institute for Surface Technologies and Photonics, Franz-Pichler Straße 30, Weiz A-8160, Austria.
authors.forename: Alexander
authors.initials: A
authors.lastname: Fian
authors.affiliation: Institute of Physics, Universitätsplatz 5, Graz A-8010, Austria.
authors.forename: Joachim R
authors.initials: JR
authors.lastname: Krenn
authors.affiliation: Chemistry of Polymeric Materials, University of Leoben, Otto Glöckel-Straße 2, Leoben A-8700, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Griesser
authors.affiliation: Materials-Institute for Surface Technologies and Photonics, Franz-Pichler Straße 30, Weiz A-8160, Austria.
authors.forename: Barbara
authors.initials: B
authors.lastname: Stadlober
keywords: Dielectrics; Organic electronics; Organic field effect transistor; Photochemistry; Thin films
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