Research directions

Scientific Research

Field emission X-ray source


        The field emission cold cathode X-ray source based on nano materials has emerged in recent years. It is considered to be a revolutionary new X-ray source technology that can replace the hot cathode technology. It has many advantages such as high spatial resolution, high temporal resolution, low power consumption and easy integration. These advantages will bring new breakthroughs to X-ray technology. For example, the use of cold cathode technology can easily realize the micro focus X-ray source, which has important applications in industrial detection, phase contrast imaging, life science research and other fields. Another most promising direction is static multi-source CT based on cold cathode X-ray source array. This CT technology uses electronic scanning to replace the traditional mechanical rotation to obtain images from different angles, which can eliminate the imaging artifacts caused by mechanical rotation, shorten the scanning time, reduce the patient's radiation dose, and improve the imaging accuracy of dynamic objects, such as beating hearts. However, clear imaging of the heart is still the difficulty of CT technology.

        After years of research, the research team has prepared carbon nanotube field emission arrays with excellent performance. The field emission performance of carbon nanotube arrays, including current density, electronic divergence, stability and life, has reached the international leading level. At present, the research group has developed a carbon nanotube cold cathode micro focus X-ray source, and combined with the self-developed three-dimensional imaging algorithm, obtained the first domestic cold cathode X-ray three-dimensional imaging image. Next, the research team will further optimize the ray source system, and use this platform technology to achieve diversified overall system integration.

Representative papers:

1. Shenghan Zhou, Ke Chen, Xiangdong Guo, Mattew Thomas Cole, Yu Wu, Zhenjun Li, Shunping Zhang,Chi Li, Qing Dai. Antenna-coupled vacuum channel nano-diode with high quantum efficiency. Nanoscale. 2020, 3

2. Chi Li#, Ke Chen#, Mengxue Guan#, Xiaowei Wang, Xu Zhou, Feng Zhai, Jiayu Dai, Zhenjun Li, Zhipei Sun, Sheng Meng*, Kaihui Liu*, Qing Dai* .Extreme nonlinear strong-field photoemission from carbon nanotubes. Nature Communications. 2019, 10:4891

3. Shenghan Zhou#, Ke Chen#, Matthew Thomas Cole, Zhenjun Li,Jun, Chen,Chi Li,* and Qing Dai*. Ultrafast Field-Emission Electron Sources Based on Nanomaterials. Advanced Materials. 2019: 201805845

4. Xiang Liu, Wenxing Zhou, Yuan Tao, Lei Mao, Jianhua Chang, Hai Hu,* Chi Li,*and Qing Dai*, Narrow-Band QD-Enhanced PIN Metal-Oxide Heterostructure Phototransistor with the Assistance of Printing Processes, Advanced Optical Materials, 2019, 1901472, DOI: 10.1002/adom.201901472.

5. Xiang Liu,* Wenjian Kuang, Haibin Ni, Zhi Tao, Jianhua Chang, Qinquan Liu, Junxiang Ge, Chi Li,* and Qing Dai*. High Efficiency Light-Emitting Transistor with Vertical Metal–Oxide Heterostructure. Small. 2018, 14(22): 1800265

6. Chi Li#, Xu Zhou#, Feng Zhai, Zhenjun Li, Fengrui Yao, Ruixi Qiao, Ke Chen, Matthew Thomas Cole, Dapeng Yu, Zhipei Sun*, Kaihui Liu*, and Qing Dai*. Carbon Nanotubes as an Ultrafast Emitter with a Narrow Energy Spread at Optical Frequency. Advanced Materials, 2017, 29(30): 1701580

7. Chi Li , Zhenjun Li , Ke Chen , Bing Bai , Qing Dai*, Edge effect enhanced photo-thermionic emission from a carbon nanotubes array, Applied Physics Letters, 2017, 110: 093105

8. Chi Li#, Xu Zhou#, Feng Zhai, Zhenjun Li,Fengrui Yao, Ke Chen, Dapeng Yu,Zhipei Sun*, Kaihui Liu*, Qing Dai*. Quiver-quenched optical-field-emission from carbon nanotubes, Applied Physics Letters, 2017, 111, 133101

9. Chi Li, Zhenjun Li, Ke Chen, Bing Bai, Qing Dai *, Electrical Driven Light Emitting From a Tunneling Junction With Negative Resistance Effect, IEEE Journal of The Electron Devices Society, 2017, 5(4): 271-274