题　目：Chirality Engineering for Ultimate Carbon Nanotube Electronics

报告人：汤代明 教授（National Institute for Materials Science, JAPAN）

时　间：2023年11月28日（周二）15:00-16:30

地　点：师昌绪楼403会议室

¹ Research Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), Namiki 1-1, Tsukuba, Ibaraki 305-0044, JAPAN

² NIMS Joint Graduate School Program, University of Tsukuba 
^* Email: TANG.Daiming@nims.go.jp

Single-wall carbon nanotubes (SWCNTs) have a one-dimensional helical tubular molecular structure made up of hexagonally bonded sp² carbon atoms. Conceptually, a SWCNT could be formed by rolling up a graphene sheet along a so-called chiral vector. The chirality of a SWCNT uniquely determines its atomic geometry and electronic structure, i.e. metallic or semiconducting. Currently, it is a great challenge to control the chirality of individual CNTs, hindering their applications in the promising energy-efficient nanotransistors. 

In our work, we developed an in situ transmission electron microscopy (TEM) probing method to monitor the chirality transition and transport properties of individual CNTs. The changes of tube structure including the chirality are stimulated by programmed bias pulses and associated Joule heating. The chirality change is analyzed by nanobeam electron diffraction. The electronic transport properties are measured along with the structural changes, via fabricating transistors using the individual nanotubes as the suspended channels.¹ 

A transition trend towards larger chiral angle region was observed and explained in terms of orientation-dependent dislocation formation energy. Controlled metal-to-semiconductor transition was realized to create nanotube transistors with a semiconducting nanotube channel covalently bonded between metallic nanotube source and drain. In addition, quantum transport at room temperature was demonstrated for the fabricated nanotube transistors with the channel length down to 2.8 nanometers.² 

In this talk, the progresses of the CNT chirality engineering will be summarized. I will discuss about the new understanding of the atomic mechanism and thermal properties of the CNT molecular junctions.³ And an outlook of the ultimate CNT electronics enabled by the chirality engineering will be presented⁴. 

References: 

1.Tang, D.-M.; Kvashnin, D. G.; Cretu, O.; Nemoto, Y.; Uesugi, F.; Takeguchi, M.; Zhou, X.; Hsia, F.-C.; Liu, C.; Sorokin, P. B.; Kawamoto, N.; Mitome, M.; Cheng, H.-M.; Golberg, D.; Bando, Y., Chirality transitions and transport properties of individual few-walled carbon nanotubes as revealed by in situ TEM probing. Ultramicroscopy 2018, 194, 108-116. 

2.Tang, D.-M.; Erohin Sergey, V.; Kvashnin Dmitry, G.; Demin Victor, A.; Cretu, O.; Jiang, S.; Zhang, L.; Hou, P.-X.; Chen, G.; Futaba Don, N.; Zheng, Y.; Xiang, R.; Zhou, X.; Hsia, F.-C.; Kawamoto, N.; Mitome, M.; Nemoto, Y.; Uesugi, F.; Takeguchi, M.; Maruyama, S.; Cheng, H.-M.; Bando, Y.; Liu, C.; Sorokin Pavel, B.; Golberg, D., Semiconductor nanochannels in metallic carbon nanotubes by thermomechanical chirality alteration. Science 2021, 374 (6575), 1616-1620. 

3.Cretu, O.; Tang, D.-M.; Lu, D.-B.; Da, B.; Nemoto, Y.; Kawamoto, N.; Mitome, M.; Ding, Z.; Kimoto, K., Nanometer-level temperature mapping of Joule-heated carbon nanotubes by plasmon spectroscopy. Carbon 2023, 201, 1025-1029. 

4.Tang, D.-M.; Cretu, O.; Ishihara, S.; Zheng, Y.; Otsuka, K.; Xiang, R.; Maruyama, S.; Cheng, H.-M.; Liu, C.; Golberg, D., Chirality engineering for carbon nanotube electronics. Nature Reviews Electrical Engineering 2024. 

Biography 

Daiming Tang is a Principal Researcher in Functional Nanomaterials Group, Research Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS). He got PhD from Institute of Metal Research (IMR), Chinese Academy of Sciences (CAS) in 2010. His main research is in situ TEM investigations for nanostructures and nanodevices.