Novel microcantilever sensor using plasmonically enhanced nonlinearity

由于其在工业，民用和军事领域的众多应用，对具有高灵敏度和选择性的微尺度传感器的需求不断增加。尽管在过去的几十年里，微尺度传感器的发展取得了迅速的进步，特别是在化学和生物传感应用方面，但对于有针对性的应用，它们的灵敏度和选择性仍然非常需要进一步提高。在这个项目中，声波产生的原理，在目标材料中使用波长相关的脉冲光吸收，以及使用高灵敏度微悬臂的检测，将用于执行分析物传感。与现有的微尺度传感器相比，将利用等离子体效应和微悬臂的非线性区域操作来放大信号，从而将检测灵敏度提高几个数量级。这项研究的成功完成预计将导致一种新型和小型化的传感器系统的发展，该系统在检测各种化学和生物分析物方面具有广泛的适用性。所开发的传感器可以对包括国防、国土安全、环境监测、公共卫生药物发现、疾病诊断和预后在内的众多领域的最新应用产生潜在的变革性影响。除了科学和社会影响外，该项目预计还将产生强大的教育影响。作为教育和推广活动的一部分，PI将培训研究生，并让本科生和高中生参与这个项目，通过利用克莱姆森大学现有的相关项目，特别注重从少数民族和代表性不足的群体中招募人才。该项目还将丰富研究生课程，建立强有力的国际合作，并通过期刊文章、会议报告和相关研究网站分享重要的科学发现。提出的研究的总体目标是利用非线性操作和等离子体效应开发一种超灵敏的谐振微悬臂传感器。这种新型传感器将结合光声检测、等离子体信号增强和非线性区域操作的优点，利用iii -氮化物压电晶体管作为偏转换能器，同时在分析物检测中提供非常高的灵敏度和选择性。采用集成AlGaN/GaN HFET偏转换能器制作的压电性GaN微悬臂梁，将利用等离子体效应进行传感，与基于Si的压电性相比，基于其独特的压电特性，可以获得更高的偏转灵敏度。作为该项目的一部分，将开发的理论模型也将大大提高我们对利用等离子体增强光声效应的非线性悬臂激励的理解。如果成功，该项目将导致微悬臂传感器的范式转变，从而开发出一种新型、高性能、多功能的传感器，与最先进的传感技术相比，该传感器具有更优越的特性。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

There is an ever increasing demand for microscale sensors with high sensitivity and selectivity due to their numerous applications spanning across industrial, civilian and military domains. Although rapid advancement in microscale sensor development, especially for chemical and biological sensing applications, has been achieved in the past decades, further enhancement in their sensitivity and selectivity is still very much desired for targeted applications. In this project, the principles of acoustic wave generation, using wavelength dependent pulsed light absorption in target materials, and detection, using a highly sensitive microcantilever, will be utilized to perform analyte sensing. Signal amplification using plasmonic effects, and non-linear region operation of the microcantilever, will be utilized to enhance the detection sensitivity by orders of magnitude compared to existing microscale sensors. Successful completion of the proposed research is anticipated to lead to the development of a novel and miniaturized sensor system with wide applicability in detecting a large variety of chemical and biological analytes. The sensors developed can have potentially transformative impacts on the state-of-the-art applications in a multitude of areas including defense, homeland security, environmental monitoring, public health drug discovery, disease diagnosis and prognosis. In addition to the scientific and societal impacts, the project is expected to have strong educational impacts as well. As a part of the educational and outreach activities, the PI would train graduate students, as well as involve undergraduate and high school students to work on this project, focusing particularly on recruitment from minority and underrepresented groups, by leveraging relevant existing programs at Clemson University. The project will also lead to enrichment of graduate courses, build strong international collaboration, and enable sharing of important scientific findings through journal articles, conference presentations, and relevant research websites.The overarching goal of the proposed research is to develop an ultrasensitive resonant microcantilever sensor using non-linear operation and plasmonic effects. This novel sensor will combine the advantages of photoacoustic detection, plasmonic signal enhancement, and non-linear region operation, utilizing a III-Nitride piezotransistor as the deflection transducer, to simultaneously offer very high sensitivity and selectivity in analyte detection. Piezotransistive GaN microcantilever, will be fabricated with integrated AlGaN/GaN HFET deflection transducer and plasmonic effects will be utilized to perform sensing, which can result in much higher deflection sensitivity based on their unique piezoelectric properties, compared to the Si based piezoresistive ones. The theoretical model to be developed as part of this project will also significantly enhance our understanding of non-linear cantilever excitation using plasmonically enhanced photoacoustic effects. If successful, the project can result in a paradigm shift in microcantilever based sensors leading to the development of a novel, high-performance and versatile sensor with much superior characteristics compared to the state-of-the-art sensing technologies.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.