Safety in … Sensors

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Ever stare into your salad and think, “today is a day of clean eating!”? Fresh, crisp veggies, lean strips of meat, a touch of balsamic dressing – nutritional happiness in a bowl. What if, however, all is not as it seems? What if the salad-springing soil was steeped in volatile pollutants? What if, within that leafy goodness, there hides micrometer sized bacteria patiently waiting to make your stomach turn? What if quality control measures lack the necessary sensitivity to ensure food safety?

We have standards and processes in place to check the quality of food reaching our markets, but last year when a leading grocery store discovered the almonds they sold contained excessive amount of cyanide, we realized the need for finer and faster sensors to detect the imperceptible.

Northeastern University, with its emphasis on use-inspired research, is a leading contributor to the field of sensing technology. A key component at the heart of sensor technology is the resonator which generates signals at precise frequencies. Of particular interest here is the MEMS resonator and NEMS resonator.

Matteo Rinaldi

Northeastern professor Matteo Rinaldi has constructed a first of its kind Aluminum Nitride Piezoelectric NEMS resonator using 2-dimensional electrode material. By integrating a 2D graphene layer (that matches, and even exceeds, the electrical conductivity of a 100x thicker gold electrode) atop A1N resonant nano-plate, Rinaldi has engineered a metal-free, ultra-high resolution, and lightning fast resonator with widespread applicability.

This 2D graphene top layer functions not only as a thin (and light) conductive electrode for exciting vibration in a piezoelectric NEMS resonator, but it also has the potential to be an effective chemical interactive material on account of its impressive surface to volume ratio. Such capacity establishes a new class of chemical sensors capable of tagging gas molecules with high throughput and unprecedented levels of sensitivity and selectivity.

Additionally, by leveraging the electric and optical properties of graphene, Rinaldi’s resonator opens a path for a new class of tunable NEMS resonant G-AlN metamaterials, which could revolutionize areas such as IR/THz sensing and RF communication.

Through the ingenuity of Matteo Rinaldi, the Aluminum Nitride Piezoelectric NEMS resonator’s remarkable sensitivity, selectivity, size, and speed stands poised to refine sensor technology. And, one of the brightest benefits of a precisely tuned sensor: Safety – we can eat our greens in peace.

Learn about Matteo Rinaldi’s Lab or for more news about Matteo Rinaldi, click here.

Want more information about this tech? Email Mark Saulich regarding “Nano and Microelectromechanical resonators.”


Written by Divya Parikh & Brice Tennant.
Cover photo by CubaGallery. All rights reserved.
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