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

这一综合研究和教育计划通过对复杂纳米场效应晶体管(FET)结构中等离子体-THz电磁辐射相互作用的系统理论和实验研究，研究了一类新的等离子体器件，用于室温下THz辐射的可调谐检测。所提出的多元等离子体激元器件将在室温下具有非常高的速度和高响应性，并且具有很宽的直流偏置连续可调谐范围。为了实现这一目标，我们将从理论、演示、实施、教育和传播等方面采取整体的方法，主要工作如下：(1)研究二维电子气等离子体与THz辐射的相互作用，包括a)单通道多栅场效应晶体管结构和b)多通道FET结构。(2)设计、制造和广泛表征所提出的器件的共振吸收和光响应特性，以演示室温可调谐的THz辐射探测。(3)工程应用装置的实现，包括THz焦平面阵列成像传感器和集成微流控通道的THz生物和化学传感器。(4)将K-20教育和代表不足的群体纳入研究活动。智力优势：太赫兹技术在医学、生物、化学、安全和太空等领域具有潜在的应用前景。这些应用中的许多都需要光谱选择性。然而，由于缺乏可调谐光源和探测器，必须使用复杂的方法(例如外差检测)或笨重的光学组件来进行频率选择。尽管传统的太赫兹探测器具有令人印象深刻的响应水平，但它们不能调谐，也不适合便携式应用。PI提出了一种变革性的等离子体激元装置技术，该技术可能导致第一个可调谐的直接探测器在室温下工作。所提出的器件是微纳尺度的半导体器件，可以很容易地与半导体电子学集成。由于其可调谐的共振吸收特性，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非常快速的可调谐滤波器。这些优势将为太赫兹光谱仪的片上实现铺平道路。这项研究还将使我们对尚未完全了解的复杂场效应管结构中的太赫兹电磁辐射-等离子体激元相互作用有一个透彻的了解，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还将有助于创建其他新型器件，如可调谐等离子体太赫兹源、光电混合器，以及具有纳米级共振元件的等离子体晶体，如量子点和等离子体纳米线。对太赫兹辐射的高效耦合和转换技术的开发还可以使在远红外和太赫兹电磁频谱范围内收集能量成为可能，而远红外和太赫兹目前还没有被广泛用作可再生能源。广泛的影响：实验工作与理论分析的集成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系、生物医学工程系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课堂。它将包括对佛罗里达州迈阿密一个以贫困和社会经济影响为主的社区的K-12学生的外展。来自金融情报院不同人群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和佛罗里达州南部科学界的研究基础设施。在现有优势的基础上，并与这些社区密切合作，PI将向全国各地的研究人员提供在该提案中开发的服务。国际和平研究所还计划通过举办国际技术讲习班和编写这方面的书籍来扩大这项工作的影响。从长远来看，可调谐太赫兹探测器的发展将通过消除对这些复杂的选频设备和/或可调谐源的需求来简化太赫兹成像和检测系统。因此，作为长期研究和可能的商业化机会的一部分，拟议的设备有可能将大量的太赫兹应用带入生活，如安全和医学成像、生物芯片、化学和生物传感以及DNA分析。

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.