Novel microcantilever sensor using plasmonically enhanced nonlinearity

Clemson University, Clemson SC

Investigators

Abstract

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.