In recent years, IBM has been looking for semiconductor materials that will continue Moore's Law. On July 10, 2014, IBM announced that it will invest 3 billion US dollars to develop 7nm chips in the next five years, and carbon nanotubes are their preferred semiconductor materials. After more than a year of research, IBM recently made a major breakthrough in carbon nanotube integrated circuit technology and solved one of the three major challenges facing commercial carbon nanotubes, namely the contact of short-channel carbon nanotube transistors (Science 2015, 350, 69-72). However, the preparation of high-purity semiconducting carbon nanotubes, the accurate positioning of carbon nanotubes, and the construction of high-performance n-type carbon nanotube transistors are still the bottleneck restricting the application of carbon nanotube integrated circuits. It remains to be further studied.
The research team led by Zhao Jianwen from the Department of Print Electronics of the Suzhou Institute of Nanotechnology and Nano-Bionics, Chinese Academy of Sciences, has been working on the development of high-performance printable semi-conducting carbon nanotube inks, high-performance printing p-type and n-type thin-film transistors since 2010. Device construction and application research. In the past few years, a variety of techniques have been developed to separate and purify semiconducting carbon nanotubes and inks. The purity of the separated semiconducting carbon nanotubes can reach over 99%. At the same time, thin-film transistor circuit systems such as CMOS inverter, simple logic circuit, ring oscillator and organic light-emitting OLED pixel driving circuit are built on the flexible and rigid substrates by using the printing preparation technology. He has published more than 10 research papers, applied for a number of invention patents, and has begun to cooperate with the industry to promote to practical applications.
Recently, the research and development of the Print Electronics Research Department has made breakthrough progress. The fully-printed flexible thin-film transistor optimized for the charge has a mobility of 100-400 cm2/Vs and a subthreshold swing (ss) of only 69 mV/dec, which is the highest mobility and subthreshold value reported in printed thin-film transistors. The smallest amplitude flexible printed carbon nanotube thin film transistor device. The printed flexible CMOS inverter has also been shown to exhibit superior performance with a gain of 23 at low voltage (1 volt) operation and a noise margin as high as 85%, which is also the best reported result in the world. The work won the "Best Paper Award" at the 6th International Conference on Flexible and Printed Electronics held in Taipei in October 2015 (ICFPE 2015).
The above work lays a good foundation for the application of printed carbon nanotube thin film transistors in the fields of new printed flexible display technology, flexible intelligent photoelectric switches and chemical biosensors.
