title: Piezotransistive transduction of femtoscale displacement for photoacoustic spectroscopy.
abstract: Measurement of femtoscale displacements in the ultrasonic frequency range is attractive for advanced material characterization and sensing, yet major challenges remain in their reliable transduction using non-optical modalities, which can dramatically reduce the size and complexity of the transducer assembly. Here we demonstrate femtoscale displacement transduction using an AlGaN/GaN heterojunction field effect transistor-integrated GaN microcantilever that utilizes piezoelectric polarization-induced changes in two-dimensional electron gas to transduce displacement with very high sensitivity. The piezotransistor demonstrated an ultra-high gauge factor of 8,700 while consuming an extremely low power of 1.36 nW, and transduced external excitation with a superior noise-limited resolution of 12.43 fm Hz(-1/2) and an outstanding responsivity of 170 nV fm(-1), which is comparable to the optical transduction limits. These extraordinary characteristics, which enabled unique detection of nanogram quantity of analytes using photoacoustic spectroscopy, can be readily exploited in realizing a multitude of novel sensing paradigms.
authors.affiliation: Department of Electrical Engineering, University of South Carolina, Columbia, South Carolina 29208, USA.
authors.forename: Abdul
authors.initials: A
authors.lastname: Talukdar
authors.affiliation: Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 2V4, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Faheem Khan
authors.affiliation: Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 2V4, Canada.
authors.forename: Dongkyu
authors.initials: D
authors.lastname: Lee
authors.affiliation: Department of Mechanical and Manufacturing Engineering, University of Calgary, Calgary, Alberta T2N 1N4, Canada.
authors.forename: Seonghwan
authors.identifier: 0000000177353582
authors.initials: S
authors.lastname: Kim
authors.affiliation: Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 2V4, Canada.
authors.forename: Thomas
authors.initials: T
authors.lastname: Thundat
authors.affiliation: Department of Electrical Engineering, Clemson University, Clemson, South Carolina 29634, USA.
authors.forename: Goutam
authors.initials: G
authors.lastname: Koley