Inkjet Printed Single Walled Carbon Nanotubes As Active Semiconductors in Thin-Film Transistors and Circuits
The materials combination of inkjet-printed single-walled carbon nanotubes (SWCNTs) and zinc tin oxide (ZTO) is very promising for large-area thin-film electronics. We compare the characteristics of conventional complementary inverters and ring oscillators measured in air (with SWCNT p-channel Thin-film transistors (TFTs) and ZTO n-channel TFTs) with those of ambipolar inverters and ring oscillators comprised of bilayer SWCNT/ZTO TFTs. This is the first such comparison between the performance characteristics of ambipolar and conventional inverters and ring oscillators. The measured signal delay per stage of 140 ns for complementary ring oscillators is the fastest for any ring oscillator circuit with printed semiconductors to date. We also demonstrate novel voltage controlled ring oscillators which are promising for analog to digital conversion circuits.