Chi Liu

Flexible Thin Film Electronics

Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang, 110016, China.








Chi Liu received the Ph.D. degree in microelectronics from Peking University, Beijing, China, in 2013. Since then, he has been a Research Scientist with the University of Tokyo, Japan. In 2016, he joined the Institute of Metal Research, Chinese Academy of Sciences, and has been a Professor since 2021.
Based on different dimensional material systems, he has constructed mixed-dimensional heterostructure electronic devices with high performance and new functions for the post-Moore era: (1) For analog devices, graphene is used to form a mixed-dimensional Schottky junction with silicon and germanium to reduce the carrier base transit time, leading to a series of high-speed graphene Schottky junction transistors, which is selected into the top 50 Nature Commun. physics articles published in 2019; (2) For optoelectronic devices, molybdenum disulfide, MXene and bulk materials are used to form mixed-dimensional heterojunctions to establish new photogating mechanisms, leading to high-performance and new functional photodetectors; (3) For digital devices, graphene is used to form a mixed-dimensional stack with metals, germanium et al. to suppress the metal induced gap state effect, leading to contact structures that effectively eliminates the Fermi level pinning effect. Research results are published in Nature Commun., Adv. Mater., Nat. Sci. Rev., Small as well as IEEE EDL and TED, et al.






Abstract for Presentation

 Mixed-dimensional heterostructure photodetectors with
high performance and new functions


Due to its atomic thickness and unique energy band structure, 2D semiconductor materials show unique advantages in the field of photodetector devices. However, its development faces three key problems: (1) Establishing new photo-gain mechanisms to improve the detectivity; (2) Developing processing technologies with large-area, high-resolution and compatible with mainstream semiconductor processes; (3) Increasing the array integration density.
Mixed-dimensional heterostructure devices may solve these problems by combining 3D bulk materials and 2D layered materials and making full use of their advantages. In this presentation, 3 mixed-dimensional photodetectors will be introduced [1-3]: (1) A molybdenum-based phototransistor with MoS2 channel and α-MoO3-x contact electrodes working in a photo-induced barrier-lowering (PIDL) mechanism with a record-high detectivity of 9.8×1016 cm Hz1/2 W-1, which adds to the techniques available for the fabrication of 2D material-based phototransistors with an ultrahigh photosensitivity. (2) A 1024-pixel high-performance MXene image sensor array fabricated by a wafer-scale combination patterning method of a MXene film with a resolution up to 2 μm, which is at least 100 times higher than other large-area patterning methods, paving a way for large-scale high-performance MXetronics compatible with mainstream semiconductor processes. (3) A MoS2 photon-controlled diode with an unusual signal processing behavior that can change the output current from the cut-off to the rectified state after illumination, leading to the first anti-crosstalk photomemory array without any selectors to increase the integration level, paving the way for future high-integration, low-power and intelligent optoelectronic systems.










 [1]    S. Feng#, C. Liu#, Q. Zhu, X. Su, W. Qian, Y. Sun, C. Wang, B. Li, M. Chen, L. Chen, W. Chen, L. Zhang, C. Zhen, F. Wang, W.Ren, L.Yin*, X. Wang*, H.-M. Cheng*, D.-M. Sun*, Nature Commun., 12 (2021) 4094.


[2]     B. Li#, Q.-B. Zhu#, C. Cui#, C.Liu*, Z.-H. Wang, S.Feng, Y. Sun, H.-L. Zhu, X. Su, Y.-M. Zhao, H.-W. Zhang, J. Yao, S. Qiu, Q.-W. Li, X.-M. Wang*, X.-H.Wang*, H.-M. Cheng, D.-M. Sun*, Adv. Mater., 34 (2022) 2201298.
[3]     S. Feng#, R. Han#, L. Zhang#, C. Liu*, B. Li, H. Zhu, Q.-B. Zhu, W. Chen, H.-M. Cheng*, D.-M. Sun*, Nat. Sci. Rev., (2022) nwac088.