[paper] THz MOST based on aligned carbon nanotube arrays

Jianshuo Zhou, Zipeng Pan, Li Ding, Lin Xu, Xiaohan Cheng, Haitao Li, Fenfa Yao, Chuanhong Jin, Maguang Zhu, Lijun Liu, Huiwen Shi, Zhiyong Zhang and Lian-Mao Peng

Terahertz metal–oxide–semiconductor transistors based on aligned carbon nanotube arrays. 

Nat Electron (2025)

DOI: https://doi.org/10.1038/s41928-025-01463-6

1. Key Laboratory for the Physics and Chemistry of Nanodevices and Center for Carbon-based Electronics, Peking University
2. Hunan Institute of Advanced Sensing and Information Technology, Xiangtan University, Xiangtan, China
3. Chongqing Institute of Carbon-based Integrated Circuits, Peking University, Chongqing, China
4. Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
5. State Key Laboratory of Silicon and Advanced Semiconductor Materials, Zhejiang University, Hangzhou, China
6. Frontiers Science Center for Nano-optoelectronics, Peking University, Beijing, China

Abstract: Films of aligned semiconducting carbon nanotubes could be used to build complementary metal–oxide–semiconductor field-effect transistors for digital integrated circuits and radio-frequency transistors for terahertz analogue integrated circuits. However, the operating frequencies of such devices remains too low for potential application in the sixth generation of wireless communications. Here we report metal–oxide–semiconductor field-effect transistors that are based on aligned carbon nanotube films and have a cut-off frequency beyond 1 THz. By optimizing gate structures and fabrication processes, we create devices with a gate length of 80 nm that have a carrier mobility of over 3,000 cm2 V−1 s−1, as well as an on-state current of 3.02 mA µm−1, a peak transconductance of 1.71 mS μm−1 at a bias of −1 V, and a saturation velocity of 3.5 × 107 cm s−1. By introducing a Y-shaped gate, we also create devices with gate lengths of 35 nm that have an extrinsic cut-off frequency (fT) of up to 551 GHz and a maximum oscillation frequency (fmax) of 1,024 GHz. Finally, we use devices with a gate length of 50 nm to fabricate mmWave-band (30 GHz) radio-frequency amplifiers that have a gain of up to 21.4 dB.

Fig: Characteristics of Y-gate structure in A-CNT MOSFETs.

Acknowledgements: This work is supported by the National Key Research & Development Program (grant number 2022YFB4401603 to L.D.) and Natural Science Foundation of China (grant numbers 62171004 to L.D., 92477201 to L.-M.P. and 62225101 to Z.Z.).