You are here

PhD Defense: Yu Hui


Frost Lounge on the first floor of Ell Hall

April 24, 2015 10:00 am to 11:30 am
Cost: Free
April 24, 2015 10:00 am to 11:30 am

Title: Aluminum Nitride Piezoelectric Microelectromechanical Resonant Physical Sensors

Miniaturized sensors are nowadays found in a wide variety of application, such as smart mobile devices, automotive, healthcare and environmental monitoring. The recent advancements of Micro/Nano-Electro-Mechanical Systems (MEMS/NEMS) technology have a tremendous impact on the sensor miniaturization, power consumption and cost reduction, which allow envisioning a new era of senor fusion in which the data collected from multiple individual sensors are combined to get information about the environment that is more accurate and reliable than the individual sensory data. This trend towards sensor fusion has dramatically increased the demand of new technology platforms, capable of delivering multiple sensing and wireless communication functionalities in a small foot print. In this perspective, the unique capability of Aluminum Nitride (AlN) piezoelectric MEMS/NEMS resonant technology to deliver high performance resonant sensors (i.e. accelerometers and gyroscopes) and radio frequency (RF) components (i.e. filters and oscillators) makes it the best platform for the implementation of the next generation miniaturized, low power, multi-functional and reconfigurable wireless sensing and communication system.

In this dissertation, a stepping stone towards the development of compact, power efficient and high resolution physical sensors: infrared (IR) detectors and magnetic field sensors, is set by taking the unique advantage of the AlN MEMS/NEMS resonant technology, which is the combination of extremely high sensitivity to external perturbations (due to their very reduced dimensions) and ultra-low noise performance (due to the intrinsically high quality factor, Q, of such resonant devices). For the first time, a spectrally selective uncooled NEMS resonant IR detector based on a plasmonic piezoelectric material is demonstrated, showing high resolution (noise equivalent power of 2.1 nW/rt-Hz) and ultra-fast response (thermal time constant of 440 μs), marking a milestone towards the implementation of a new class of high performance, miniaturized and low power IR spectroscopy and multi-spectral imaging systems. On the other hand, the proposed magnetic field sensor based on a piezoelectric and magnetostrictive bilayer of AlN/FeGaB showed a detection limit of 16 nT/rt-Hz and angular resolution of 0.34°, proofing its potential for the application of extremely small magnetic field detection and miniaturized electronic compasses for mobile devices.

Professor Matteo Rinaldi, Advisor
Professor Nick McGruer, Committee Member
Professor Nian Sun, Committee Member
Professor Yongmin Liu, Committee Member