Low-voltage high-performance flexible digital and analog circuits based on ultrahigh-purity semiconducting carbon nanotubes

Abstract

Carbon nanotube (CNT) thin-film transistor (TFT) is a promising candidate for flexible and wearable electronics. However, it usually suffers from low semiconducting tube purity, low device yield, and the mismatch between p- and n-type TFTs. Here, we report low-voltage and high-performance digital and analog CNT TFT circuits based on high-yield (19.9%) and ultrahigh purity (99.997%) polymer-sorted semiconducting CNTs. Using high-uniformity deposition and pseudo-CMOS design, we demonstrated CNT TFTs with good uniformity and high performance at low operation voltage of 3 V. We tested forty-four 2-µm channel 5-stage ring oscillators on the same flexible substrate (1,056 TFTs). All worked as expected with gate delays of 42.7 ± 13.1 ns. With these high-performance TFTs, we demonstrated 8-stage shift registers running at 50 kHz and the first tunable-gain amplifier with 1,000 gain at 20 kHz. These results show great potentials of using solution-processed CNT TFTs for large-scale flexible electronics.

Stable and Biocompatible Carbon Nanotube Ink Mediated by Silk Protein for Printed Electronics

“…Carbon nanotubes (CNTs) are considered as a type of ideal active materials for flexible electronics because of their unique electrical properties, mechanical robustness and high stability. [9,12,[16][17][18][19][20][21][22][23] However, the poor dispersity of CNTs hinders the development of CNT-based conductive inks. CNTs tend to tightly aggregate due to strong π-π interactions between each other, and are thus difficult to be dispersed in a liquid phase, especially in water.…”

Ink‐Based Additive Nanomanufacturing of Functional Materials for Human‐Integrated Smart Wearables

“…Thanks to the high carrier mobility, large-area capability, and low processing temperature, semiconducting CNTs have been used to fabricate high-performance thin-film transistors on flexible substrates. [551][552][553][554] The printed CNT networks are used as channel materials, and rapid progress has been achieved on the separation of metallic and semiconducting CNTs, [362,364] and deposition of well-aligned CNTs channels along the sourceto-drain direction. [555,556] For example, Jang et al fabricated short-channel (150-200 nm) FET using inkjet printing of semiconducting CNTs, [557] which exhibited a mobility value of 24 cm 2 V À1 s À1 at an operation voltage of 0.5 V. The doped CNTs (p type and n type CNTs) have also been used to fabricate CMOS devices.…”

Process design kit and design automation for flexible hybrid electronics

“…(A)‐(C) Pseudo‐CMOS flip‐flop schematics and measured waveforms, (D)‐(F) shift‐register schematics and measured waveforms, and (G)‐(J) variable gain amplifier (VGA) schematics, measured waveforms, and frequency response…”

“…In this paper, complex sequential logic circuits such as shift registers are demonstrated using only p-type CNT-TFTs as shown in Figure 8D,F, in which shift registerthe 50 KHz clock is used as the input, and the measured output waveforms of the cascaded registers after eight stages do not show any noticeable signal degradations, even with only p-type CNT-TFTs. 3 With the aids of trustworthy simulation models and design rules developed for FHE-PDK, we can now readily design, simulate, and verify complex TFT digital logic circuits with thousands of CNT-TFTs using popular electronics design and verification tools such as Cadence Virtuoso and Mentor Graphics Calibre. The simulated TFT circuit performance and power consumption also provide a good correlation with the fabricated CNT-TFT circuits at low supply voltages (3 V).…”