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A facile, high-resolution patterning process is introduced for fabrication of electrolyte-gated transistors (EGTs) and circuits using a photo-crosslinkable ion gel and stencil-based screen printing. The photo-crosslinkable gel is based on a triblock copolymer incorporating UV-sensitive terminal azide functionality and a common ionic liquid. Using this material in conjunction with conventional photolithography and stenciling techniques, well-defined 0.5–1 μm thick ion gel films are patterned on semiconductor channels as narrow as 10 μm. The resulting n-type ZnO EGTs display high electron mobility (>2 cm2 Vs−1) and on/off current ratios (>105). Further, EGT-based inverters exhibit static gains >23 at supply voltages below 3 V, and five-stage EGT ring oscillator circuits display dynamic propagation delays of 50 μs per stage. In general, the screen printing and photo-crosslinking strategy provides a clean room-compatible method to fabricate EGT circuits with improved sensitivity (gain) and computational power (gain × oscillating frequency). Detailed device analysis indicates that significantly shorter delay times, of order 1 μs, can be obtained by improving the ion gel conductance.
Bibliographical noteFunding Information:
This work was primarily supported by the MRSEC program of the National Science Foundation under Grant Number DMR-1420013. F.Z. is grateful to Xinglong Ren and Yan Wang for discussions. K.S.J. acknowledges support from the National Science Foundation (NSF) Graduate Research Fellowship Program under Grant No. (00039202). Parts of this work were carried out in the Characterization Facility, University of Minnesota, which receives partial support from the NSF through the MRSEC program. Portions of this work were conducted in the Minnesota Nano Center, which is supported by the National Science Foundation through the National Nano Coordinated Infrastructure Network (NNCI) under Award Number ECCS-1542202. C.D.F. and F.Z. conceived the project. B.T. synthesized and optimized the SEAS-N3 polymer under the direction of T.P.L. F.Z. fabricated the devices. F.Z. developed the screen printing in collaboration with W.J.H. S.J.K, F.Z., and R.M. characterized the electrical properties of the devices. F.Z. analyzed the data with discussion with C.D.F., K.S.J., and D.S. All the authors collaborated in writing the paper and agreed on the final version.
© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
- electrolyte-gated transistors
- ion gels
- screen printing
How much support was provided by MRSEC?
Reporting period for MRSEC
- Period 6