黑磷太赫兹光电响应的热电子放大机理及其调控研究

Terahertz technology is very promising in application in the fields of THz-radar, astronomy, security and biomedical imaging, however it is still lagged behind due to lack of reliable solid-state detection technique. Low-dimensional materials such as black phosphorus open up intriguing prosperities for the development of uncooled THz detectors, owing to their highly controllable physical properties such as optics, thermodynamics and electronics. This project with solve with the bottlenecks confronted by traditional solid-state detectors, which are suffering from stringent cooling conditions, low response speed etc., and the difficulties of traditional antenna technology in both the high collection efficiency and the high degree of integrability. This project will develop a novel strategy of THz detection with hot electron multiplication and its regulation based on the black phosphorus like material system. Under the objective of high degree array integration, this project will study in-depth the electromagnetic focusing due to the size effect of subwavelength structures, and solves the difficulty of efficient integration between these structures and the field effect structures in black phosphorus system. Through symmetric/asymmetric contacts/coupler designing and material's characterization microscopically, the underlying dynamic mechanisms of hot electron generation, multiplication and the photoelectric conversion under modulations of both the field effect and electromagnetic effect will be clarified. This project will ultimately develop a hot electron THz detector with high gain under the synergetic effects of electromagnetic and electric field modulations. Through the innovation of experiment, theory and technology, this project will open a route toward high performance terahertz device design and its room temperature imaging application based on black phosphorus system. The results will also pave an important foundation toward a new generation terahertz detector with flexibility, fast response as well as high-sensitivity.

太赫兹技术在雷达、天文、安检与生物成像等领域具有广阔的应用前景，而缺少相应的固态探测技术是制约其发展的重要因素。以黑磷为代表的低维材料所呈现的高度可控的光、热、电等性质为非制冷型探测器的研究与发展提供了新的平台。本项目将围绕解决传统固态探测需要制冷、响应速度慢等瓶颈问题，以及传统器件、天线所面临的高效耦合与高度集成的技术难点，发展新型的基于黑磷体系的热电子放大探测原理及其调控方法。以高度阵列化需求为目标，深入研究亚波长结构电磁尺寸聚焦现象及其与黑磷体系场效应电学集成，通过非对称/对称接触、耦合设计以及微观表征，揭示场效应调控与电磁调控下黑磷表面热电子产生、放大及其光电转换机制，通过两者的有机结合实现基于热电子效应的高增益探测器结构。通过实验、理论方法和技术的创新，建立高性能热电太赫兹探测器件的设计方法并实现其成像演示功能，为新一代柔性、高速、高灵敏太赫兹探测器及其应用奠定重要科学基础。

围绕太赫兹波光电技术在空间天文、国防安全、雷达通讯等国家关键领域的重大需求，以及传统光电探测技术面临着工作温度、集成化、灵敏度等导致的太赫兹光电核心发展壁垒，本项目着重围绕黑磷为代表的新型二维材料光电探测理论、器件实验方法开展研究，包括太赫兹光子辐射耦合效应、人工微纳天线耦合集成、黑磷等二维材料非平衡热电子效应以及半金属材料量子态特征耦合的非线性光电转换等方面研究，揭示了亚趋肤深度极限光场汇聚与响应增强机制，实现了基于二维原子界面异质构筑的非平衡热电子探测与原子时空反演对称保护的非线性拓扑响应，解决了电磁耦合、非平衡态增益与无序高转换抑制等限制探测器性能的关键科学问题，并形成二维材料构筑-新器件机理验证与应用演示的创新链，研究工作实现了基于黑磷等二维材料的高性能探测与成像功能，灵敏度突破1pW/Hz^0.5，获得国际报道的最佳性能。研究工作在Nat. Commun.、Sci. Adv.、Light:Sci.&Appl.、Nano Lett.等国际顶级刊物上发表SCI 论文10篇，申请专利3项，成果被科普中国、科学网、Materialviews等国际权威学术媒体网站亮点报道，被国际同行多次拷贝式引用，形成基于黑磷为代表的二维电子材料非平衡操控与高性能太赫兹探测功能实现的可行途径。