Flexible CMOS‐Like Circuits Based on Printed P‐Type and N‐Type Carbon Nanotube Thin‐Film Transistors

Abstract

P‐type and n‐type top‐gate carbon nanotube thin‐film transistors (TFTs) can be selectively and simultaneously fabricated on the same polyethylene terephthalate (PET) substrate by tuning the types of polymer‐sorted semiconducting single‐walled carbon nanotube (sc‐SWCNT) inks, along with low temperature growth of HfO 2 thin films as shared dielectric layers. Both the p‐type and n‐type TFTs show good electrical properties with on/off ratio of ≈10 5 , mobility of ≈15 cm 2 V −1 s −1 , and small hysteresis. Complementary metal oxide semiconductor (CMOS)‐like logic gates and circuits based on as‐prepared p‐type and n‐type TFTs have been achieved. Flexible CMOS‐like inverters exhibit large noise margin of 84% at low voltage (1/2 V dd = 1.5 V) and maximum voltage gain of 30 at V dd of 1.5 V and low power consumption of 0.1 μW. Both of the noise margin and voltage gain are one of the best values reported for flexible CMOS‐like inverters at V dd less than 2 V. The printed CMOS‐like inverters work well at 10 kHz with 2% voltage loss and delay time of ≈15 μs. A 3‐stage ring oscillator has also been demonstrated on PET substrates and the oscillation frequency of 3.3 kHz at V dd of 1 V is achieved.