CAREER: Nanoscale Multi-element Plasmonic Devices for Tunable THz Detection Applications

这个综合研究和教育计划通过系统的理论和实验研究在复杂的纳米场效应晶体管（FET）结构中等离子体-太赫兹电磁辐射相互作用，研究了一种新的等离子体器件家族，用于在室温下可调谐探测太赫兹辐射。所提出的多元件等离子体器件在室温下具有非常高的速度和高响应性，并且在直流偏置下具有大范围的连续可调性。为了达到既定目标，将采用理论、论证、实施、教育和传播的整体方法，主要任务如下：(1)二维电子气体等离子体-太赫兹辐射在a)单通道多栅极场效应管结构和b)多通道场效应管结构中的相互作用的理论研究。(2)设计、制造和广泛表征谐振吸收和光响应特性，以演示室温可调谐太赫兹辐射检测。(3)工程应用器件包括太赫兹焦平面阵列成像传感器和集成微流控通道的太赫兹生物和化学传感器的实现。(4)将K-20教育和弱势群体纳入研究活动。知识价值：太赫兹技术在医学、生物、化学、安全和空间方面有潜在的应用。许多这些应用都需要光谱选择性。然而，由于缺乏可调谐源和检测器，需要使用复杂的方法（例如外差检测）或笨重的光学元件进行频率选择。尽管其令人印象深刻的响应水平，传统太赫兹探测器是不可调的或适合便携式应用。PI提出了一种变革性等离子体器件技术，这可能会导致第一个在室温下工作的可调谐直接探测器。提出的器件是微/纳米级半导体器件，可以很容易地与半导体电子集成。由于其可调谐的谐振吸收特性，所提出的等离子体器件也可以用作其他太赫兹探测方法的快速可调谐滤波器。这些优点将为太赫兹光谱芯片的发展铺平道路。提出的研究也将导致对复杂FET结构中尚未完全理解的太赫兹电磁辐射-等离子体相互作用的透彻理解，并将扩展我们在等离子体科学方面的知识。将开发和测试的分析和数值模型也将有助于创建其他新设备，如可调谐等离子体太赫兹源，光电混合器和具有纳米级共振元件（如量子点和等离子体纳米线）的等离子体晶体。太赫兹辐射的有效耦合和转换技术的发展也可以使远红外线和太赫兹范围内的电磁频谱的能量收集成为可能，这是目前尚未被广泛利用的可再生能源。更广泛的影响：实验工作与理论分析的整合将为佛罗里达国际大学的研究生和本科生提供宝贵的经验，并在电气与计算机工程、生物医学工程和医学院之间创造协同作用，引领拟议设备技术的新应用。一项补充教育计划将制定一项计划，将太赫兹技术和纳米技术的进步知识传播到高中和大学教室。它将包括向佛罗里达州迈阿密一个主要贫困和社会经济受影响的社区的K-12学生伸出援手。来自FIU不同人口的几名本科生将积极参与拟议的研究活动。教育部分还包括指导两名研究生和开发一门关于太赫兹技术和应用的研究生课程。拟议的计划将通过支持FIU太赫兹研究实验室，加强FIU和南佛罗里达科学界的研究基础设施。利用现有优势，与这些社区密切合作；PI将使该提案中开发的服务可供全国的研究人员使用。PI还计划通过国际技术讲习班和在该领域编辑的书籍来增加这项工作的影响。从长远来看，可调谐太赫兹探测器的发展将通过消除这些复杂的频率选择装置和/或可调谐源的必要性来简化太赫兹成像和探测系统。因此，所提出的设备具有将大量太赫兹应用带入生活的潜力，例如安全和医学成像，生物芯片，化学和生物传感以及DNA分析，作为长期研究和可能的商业化机会的一部分。

This integrated research and education plan investigates a new family of plasmonic devices for tunable detection of THz radiation at room temperature through systematic theoretical and experimental study of plasmon-THz electromagnetic radiation interactions in complex nano-scale Field Effect Transistor (FET) structures. The proposed multi-element plasmonic devices will have very high speed and high responsivity at room temperature with wide range of continuous tunability by DC bias. To reach the stated goal a holistic approach with its theory, demonstration, implementation, education and dissemination will be adopted with the following major tasks: (1) Theoretical study of 2D electron gas plasmons-THz radiation interactions in a) single-channel multi-gate FET structures and b) multi-channel FET structures.(2) Design, fabrication and extensive characterization of resonant absorption and photoresponse characteristics of the proposed devices to demonstrate room temperature tunable detection of THz radiation. (3) Implementation of the proposed devices for engineering applications including THz focal plane array imaging sensors and THz biological and chemical sensors with integrated microfluidic channels. (4) Integration of K-20 education and underrepresented groups into research activities.Intellectual Merit: THz technology has potential applications in medicine, biology, chemistry, security, and space. Many of these applications require spectral selectivity. However lack of tunable sources and detectors necessitates the use of complex methods (e.g. heterodyne detection) or bulky optical components for frequency selection. Despite their impressive responsivity levels, conventional THz detectors are not tunable or suitable for portable applications. The PI proposes a transformative plasmonic device technology which could lead the first tunable direct detectors operating at room temperature. The proposed devices are micro/nano-scale semiconductor devices which can be easily integrated with semiconductor electronics. With their tunable resonant absorption characteristics, proposed plasmonic devices can also be used as very fast tunable filters for other THz detection methods. These advantages will pave the way for THz-spectrometer-on-chip. The proposed research will also result in a thorough understanding of the THz electromagnetic radiation-plasmon interactions in complex FET structures which have not been fully understood yet and will expand our knowledge in the science of plasmonics. Analytical and numerical models which will be developed and tested will also help to create other novel devices such as tunable plasmonic THz sources, photomixers, and plasmonic crystals with nanoscale resonance elements such as quantum dots and plasmonic nanowires. Development of efficient coupling and conversion techniques for THz radiation can also make energy harvesting possible in far infrared and THz range of the electromagnetic spectrum which is currently not exploited as a widely available renewable energy source.Broader Impact: The integration of experimental effort along with theoretical analysis will offer invaluable experiences to graduate and undergraduate students at Florida International University and create synergy between departments of Electrical & Computer Engineering, Biomedical Engineering and College of Medicine leading new applications for the proposed device technology. A complementary education plan will develop a program for disseminating knowledge of the advancements in THz technology and nanotechnology into high school and university classrooms. It will include an outreach to K-12 students in a predominantly underprivileged and socio-economically impacted neighborhood of Miami, FL. Several undergraduate students from the diverse population of FIU will be actively involved with the proposed research activities. Education component also includes supervising two graduate students and development of a graduate course on THz technology and applications. Proposed plan will enhance the research infrastructure for the scientific communities at FIU and in south Florida by supporting the FIU THz Research Lab. Building on existing strengths and closely working with these communities; the PI will make the services developed within this proposal available to researchers across the nation. The PI is also planning to increase the impact of this work via international technical workshops, and an edited book in this area. In the long run, development of tunable THz detectors will simplify the THz imaging and detection systems by eliminating necessity of these complex frequency selection apparatus and/or tunable sources. Therefore the proposed devices have the potential of bringing an abundance of THz applications into life such as security and medical imaging, biochips, chemical and biological sensing and DNA analysis as part of a long-term research and possible commercialization opportunities.