Exploring lateral photo-Dember effect in two dimensional atomic layer crystals for terahertz generation

在0.1~10太赫兹范围内有效产生长波长辐射仍然是太赫兹技术在高速通信、光谱学和成像应用中的发展和部署的关键挑战。本研究项目探讨了一种独特的横向光致伸缩效应在二维纳米材料的太赫兹产生。该项目将为开发具有广泛应用的新型紧凑型太赫兹源打开大门。此外，通过拟议的研究获得的知识和技术可以很容易地扩展到研究其他类型的一维和二维纳米材料的超快光学物理。更广泛地说，拟议的项目是高度跨学科的，应该推进纳米材料，光学科学，纳米电子学，纳米光子学和器件物理学领域的科学和技术。该项目还包括一个推广和教育计划，促进K-12和本科生对纳米科学和纳米技术的认识和兴趣。 该项目产生的知识和研究成果将被整合到目前正在开发的一些新的纳米技术课程中，这些课程与碳纳米技术，光学科学和纳米光子学有关。本研究计划旨在了解石墨烯和少层过渡金属二硫族化物等二维原子层晶体中基本的横向光致伸缩效应，并开发基于这些二维纳米材料的新型太赫兹源。项目任务是：（1）开展基础研究，深入了解石墨烯和过渡金属二硫族化合物中的超快光载流子动力学;（2）制备和表征金属/二维纳米材料结的太赫兹发射;（3）设计基于二维纳米材料的新型太赫兹发射器阵列并测试其性能。本项目将开发和利用二维纳米材料的先进光电表征技术，包括扫描光电流测量、超快泵浦-探测光电流测量和太赫兹时域光谱技术。该项目的成功将产生对低维纳米材料中光-物质相互作用和超快载流子动力学的基本和详细的了解。此外，该项目的发现将真正展示二维纳米材料在独特的光电应用中的优势，这在块状半导体中是不可能的。

The efficient generation of long wavelength radiation at the 0.1~10 terahertz region remains a key challenge for the development and deployment of terahertz technology for high speed communication, spectroscopy, and imaging applications. This research project explores a unique lateral photo-Dember effect in 2-dimensional nanomaterials for terahertz generation. The proposed project will open a door to developing new type of compact terahertz sources with a broad range of applications. In addition, the knowledge and techniques acquired through the proposed research can readily be extended to study ultrafast optical physics of other type of 1-dimensional and 2-dimensional nanomaterials. More broadly, the proposed project is highly interdisciplinary and should advance science and technology in areas of nanomaterials, optical science, nanoelectronics, nanophotonics, and device physics. The project also includes an outreach and education program promoting awareness of and interest in nanoscience and nanotechnology among K-12 and undergraduate students. The knowledge and research findings resulting from this project will be integrated into a number of new nanotechnology courses currently under development that are related to carbon nanotechnology, optical science, and nanophotonics. This project will be further enhanced by proactively recruiting underrepresented students, which can improve the diversity of science, technology, engineering, and mathematics disciplines and workforce.This research project aim to understand the fundamental lateral photo-Dember effect in 2-dimensional atomic layer crystals including graphene and few layer transition metal dichalcogenides, and to pioneer new terahertz sources based on these 2-dimensional nanomaterials. The project tasks are: (1) to perform fundamental study to thoroughly understand the ultrafast photo-carrier dynamics in graphene and transition metal dichalcogenides; (2) to fabricate and characterize the terahertz emission from metal/2-dimensional nanomaterial junctions; (3) to design new terahertz emitter arrays based on 2-dimensional nanomaterials and test their performance. A combination of advanced optoelectronic characterization techniques for 2-dimensional nanomaterials will be developed and utilized in this project, including scanning photocurrent measurement, ultrafast pump-probe photocurrent measurement, and terahertz time-domain spectroscopy techniques. The success of the project will generate fundamental and detailed understanding of light-matter interaction and ultrafast carrier dynamics in low dimensional nanomaterials. In addition, the finding of the project will truly showcase the advantages of 2-dimensional nanomaterials for unique optoelectronic applications which are not possible in bulk semiconductors.