Self-Aligned Organic Field-Effect Transistors On Plastic With Picofarad Overlap Capacitances And Megahertz Operating Frequencies

Stuart G. Higgins, Beinn V. O. Muir, Giorgio Dell'Erba, Andrea Perinot, Mario Caironi, Alasdair J. Campbell

Appl. Phys. Lett. 108 023302 (2016), doi: 10.1063/1.4939045
Supporting data: doi: 10.5281/zenodo.35592

Image © 2016 Higgins  et al.  CC-BY

Image © 2016 Higgins et al. CC-BY

'Using a combination of nanoimprint lithography, gate-source/drain self-alignment, and gravure and inkjet printing, we fabricate organic field-effect transistors on flexible plastic substrates with gate-source and gate-drain electrode overlap capacitances of COL < 1 pF, equivalent to channel-width normalised capacitances of C*OL = 0.15–0.23 pF mm−1. We compare photopatterned and nanoimprint lithography patterned channels of L ≈ 3.8 μm and L ≈ 800 nm, respectively. The reduction in L was found on average to result in order of magnitude greater switching frequencies. Gravure printing the dielectric (versus photo-patterning) was found to yield an order of magnitude lower overlap capacitance C*OL = 0.03 pF mm−1, at the expense of greater processing variation. Inkjet printed p- and n-type polymeric organic semiconductors were used to fabricate organic-field effect transistors with a peak cutoff frequencies of fS = 9.0 ± 0.3 MHz at VGS = 30 V, and transition frequencies of fT = 3.3 ± 0.2 MHz at VGS = 30 V.'


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