Wafer-Scale Fabrication and Characterization of Thin-Film Transistors with Polythiophene-Sorted Semiconducting Carbon Nanotube Networks

Abstract

Semiconducting single-walled carbon nanotubes (SWCNTs) have great potential of becoming the channel material for future thin-film transistor technology. However, an effective sorting technique is needed to obtain high-quality semiconducting SWCNTs for optimal device performance. In our previous work, we reported a dispersion technique for semiconducting SWCNTs that relies on regioregular poly(3-dodecylthiophene) (rr-P3DDT) to form hybrid nanostructures. In this study, we demonstrate the scalability of those sorted CNT composite structures to form arrays of TFTs using standard lithographic techniques. The robustness of these CNT nanostructures was tested with Raman spectroscopy and atomic force microscope images. Important trends in device properties were extracted by means of electrical measurements for different CNT concentrations and channel lengths (<i>L</i>_c). A statistical study provided an average mobility of 1 cm²/V·s and <i>I</i>_on/<i>I</i>_off as high as 10⁶ for short channel lengths (<i>L</i>_c = 1.5 μm) with 100% yield. This highlights the effectiveness of this sorting technique and its scalability for large-scale, flexible, and transparent display applications.