Materials

Wissenschaftliche Publikation

Switching from weakly to strongly limited injection in self-aligned, nano-patterned organic transistors

Publikation aus Materials

Karin Zojer, Thomas Rothländer, Johanna Kraxner, Roland Schmied, Mag.a Dr.in Ursula Palfinger, Harald Plank, Werner Grogger, DIin Dr.in Anja Haase, Mag. Dr. Herbert Gold, Barbara Stadlober

Sci. Rep. 6, 31387; doi: 10.1038/srep31387 , 9/2016

Abstract:

Organic thin-film transistors for high frequency applications require large transconductances in combination with minimal parasitic capacitances. Techniques aiming at eliminating parasitic capacitances are prone to produce a mismatch between electrodes, in particular gaps between the gate and the interlayer electrodes. While such mismatches are typically undesirable, we demonstrate that, in fact, device structures with a small single-sided interlayer electrode gap directly probe the detrimental contact resistance arising from the presence of an injection barrier. By employing a self-alignment nanoimprint lithography technique, asymmetric coplanar organic transistors with an intentional gap of varying size (< 0.2??m) between gate and one interlayer electrode are fabricated. An electrode overlap exceeding 1??m with the other interlayer has been kept. Gaps, be them source or drain-sided, do not preclude transistor operation. The operation of the device with a source-gate gap reveals a current reduction up to two orders of magnitude compared to a source-sided overlap. Drift-diffusion based simulations reveal that this marked reduction is a consequence of a weakened gate-induced field at the contact which strongly inhibits injection.