Graphene on Nanoscale Gratings for Terahertz Light Emission

该项目由材料研究部（DMR）的电子和光子材料计划（EMT）以及电气，通信和网络系统部（ECCS）的电子，光子学和磁器件计划（EPMD）共同资助。技术说明：该项目的目标是在纳米级光栅上开发高质量的石墨烯样品，用于基于新颖的辐射机制产生太赫兹（THz）光，迄今为止，这种辐射机制一直是真空系统中高能电子束的主要领域。具体而言，正在研究的机制包括一个全新的回旋加速器式发射过程，其中角运动是通过几何约束而不是通过施加外部磁场获得的，以及史密斯-珀塞尔效应。该项目活动涉及用于制造高度正弦纳米级光栅的纳米光刻、通过剥离和高真空化学气相沉积合成石墨烯、石墨烯转移以及通过门控电研究、拉曼光谱和太赫兹辐射测量表征样品。石墨烯的独特性质（包括其线性能量色散，高电子速度和迁移率以及二维性质）非常适合研究中的辐射机制。与此同时，通过对这些现象的演示和研究，可以揭示有关基础材料物理学的关键信息。非技术描述：石墨烯是一种二维晶体，由单层碳原子排列成蜂窝状晶格。凭借其独特的电子、光学和机械性能，它代表了一个有前途的材料平台，使电子和光子技术能够朝着不断提高的性能、小型化和功能性的方向不断发展，远远超出了传统半导体的基本限制。该项目研究使用这些属性开发一个新的范例太赫兹光发射在紧凑的固态系统。因此，它可能为一类新的THz设备开辟道路（包括可能能够在室温下工作的THz激光器，与所有现有的基于半导体的解决方案不同），这是安全筛选，医疗诊断和制造质量控制等广泛新兴应用所需的。在这些活动的过程中，通过在材料科学和纳米技术的几个领域对学生进行培训来促进教育，除博士外，还特别强调本科生和高中实习生的参与。候选人一个相关的目标是基于研究方法和成果的实验模块的开发，以提高在波士顿大学（BU）的纳米技术本科课程的实验室组成部分，并在当地高中（包括具有大量少数民族人口的研究所）的本科生参与BU灵感大使计划的示范。

This project is jointly funded by the Electronic and Photonic Materials Program (EPM) in the Division of Materials Research (DMR) and the Electronics, Photonics, and Magnetic Devices Program (EPMD) in the Division of Electrical, Communications and Cyber Systems (ECCS). Technical Description: The goal of this project is to develop high-quality graphene samples on nanoscale gratings for the generation of terahertz (THz) light based on novel radiation mechanisms that so far have been the primary domain of high-energy electron beams in vacuum-based systems. Specifically, the mechanisms under study include a radically new cyclotron-like emission process, where angular motion is obtained via geometrical constraints rather than through the application of an external magnetic field, and the Smith-Purcell effect. The project activities involve a combination of nanolithography for the fabrication of highly sinusoidal nanoscale gratings, graphene synthesis via exfoliation and high-vacuum chemical vapor deposition, graphene transfer, and sample characterization via gated electrical studies, Raman spectroscopy, and THz-radiation measurements. The distinctive properties of graphene (including its linear energy dispersion, high electron velocity and mobility, and two-dimensional nature) are uniquely suited to the radiation mechanisms under study. At the same time, critical information about the underlying materials physics can be unveiled through the demonstration and investigation of these phenomena.Non-technical Description: Graphene is a two-dimensional crystal consisting of a single layer of carbon atoms arranged in a honeycomb lattice. By virtue of several unique electronic, optical, and mechanical properties, it represents a promising materials platform to enable the continued evolution of electronic and photonic technologies towards ever increasing performance, miniaturization, and functionalities, well beyond the fundamental limits of traditional semiconductors. This project investigates the use of these properties to develop a new paradigm for THz light emission in compact solid-state systems. As a result, it may open the way for a new class of THz devices (including THz lasers potentially capable of room-temperature operation, unlike all existing semiconductor-based solutions), as needed for a wide range of emerging applications in security screening, medical diagnostics, and manufacturing quality control. In the course of these activities, education is promoted through the training of students in several areas of materials science and nanotechnology, with a strong emphasis on the involvement of undergraduates and high-school interns in addition to Ph.D. candidates. A related goal is the development of experimental modules based on the research methods and outcomes, to enhance the laboratory component of an undergraduate course on nanotechnology at Boston University (BU), and for demonstrations at local high schools (including institutes with large minority populations) by undergraduates engaged in BU Inspiration-Ambassadors program.