Zhang Daoshu, Zhang Siyuan, He Ke, Wang Libin, Sui Fan, Hong Xuda, Li Weiwei, Li Nianci, Jia Meiling, Li Weimin, Wang Zhixun, Wang Zongpeng, Du Bi, Wei Lei, Feng Ye, Zhong Guohua, Li Wenjie, Chen Jun, Yang Chunlei, Chen Ming
Center for Information Photonics and Energy Materials, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, People's Republic of China.
Nano Science and Technology Institute, University of Science and Technology of China, Suzhou 215123, People's Republic of China.
Nanotechnology. 2020 Nov 27;31(48):485202. doi: 10.1088/1361-6528/abb0b6.
Full static x-ray computed tomography (CT) technology has enabled higher precision and resolution imaging and has been applied in many applications such as diagnostic medical imaging, industrial inspection and security screening. In this technique, the x-ray source section is mainly composed of a thermionic cathode and electron beam scanning system. However, they have several shortcomings such as limited scanning angle, long response time and large volume. Distributed and programmable cold cathode (i.e. carbon nanotubes, ZnO nanowires (NWs)) field-emission x-ray sources are expected to solve these problems. However, there have been several long-standing challenges to the application of such cold field emitters for x-ray sources, such as the short lifetime and rigorous fabrication process, which have fundamentally prevented their widespread use. Here, we propose and demonstrate a cold field-emission x-ray source based on a graphene oxide (GO)-coated cuprous sulfide nanowire (CuS NW/GO) cathode. The proposed CuS NW/GO x-ray source provides stable emission (>18 h at a direct voltage of 2600 V) and has a low threshold (4.5 MV m for obtaining a current density of 1 μA cm), benefiting from the demonstrated key features such as in situ epitaxy growth of CuS NWs on Cu, nanometer-scale sharp protrusions within GO and charge transfer between the CuS NWs and GO layer. Our research provides a simple and robust method to obtain a high-performance cold field emitter, leading to great potential for the next generation of x-ray source and CT.
全静态X射线计算机断层扫描（CT）技术实现了更高精度和分辨率的成像，并已应用于许多领域，如诊断医学成像、工业检测和安全筛查。在这项技术中，X射线源部分主要由热离子阴极和电子束扫描系统组成。然而，它们存在一些缺点，如扫描角度有限、响应时间长和体积大。分布式可编程冷阴极（即碳纳米管、氧化锌纳米线（NWs））场发射X射线源有望解决这些问题。然而，将这种冷场发射体应用于X射线源存在一些长期挑战，如寿命短和制造工艺严格，这从根本上阻碍了它们的广泛应用。在此，我们提出并展示了一种基于氧化石墨烯（GO）包覆的硫化亚铜纳米线（CuS NW/GO）阴极的冷场发射X射线源。所提出的CuS NW/GO X射线源提供稳定的发射（在2600 V直流电压下超过18小时），并且具有低阈值（获得1 μA cm电流密度时为4.5 MV m），这得益于所展示的关键特性，如在铜上原位外延生长CuS NWs、GO内的纳米级尖锐突起以及CuS NWs与GO层之间的电荷转移。我们的研究提供了一种简单而稳健的方法来获得高性能冷场发射体，为下一代X射线源和CT带来了巨大潜力。
