Nanoelectromechanical systems, or NEMS, are devices that contain active elements with critical dimensions below 100 nm. The study of such structures has come to prominence over the last few decades as technologies like charged-beam microscopy and atomic force microscopy have become standard techniques. The importance of NEMS lies in their scale, where physical and electrical properties of materials can be dramatically different than in the macro-world. For instance, the device shown at left is a torsional oscillator built on an individual single-wall carbon nanotube (the thin, bright line you see in the gaps to either side of the moving block). This carbon nanotube is essentially a single atomic layer of graphite rolled on to itself to form a continuous tube of carbon atoms only ~1 nm in diameter. While graphite in the macro-scale environment is not particularly special (it is what makes pencil led, for example), at the nanoscale, it exhibits some fascinating properties. When a paddle like the one in this image is actuated (using electric fields), the resistance measured through the carbon nanotube changes repeatably, creating a variable resistor or switch. This effect can tell us something about the tube itself, but can also be used to measure the motion of the moving block without the aid of a microscope.
One of the goals of our research is to utilize devices like this to act as a biological and chemical sensor. Because of the extremely small size of the active element, the resulting system could have very high sensitivity, offering early detection of air- and water-borne contaminants and toxins. There is also great potential for integrating NEMS into devices intended to analyze whole-blood samples for fast and accurate diagnosis.
You can find out more about these efforts at our publications page, or by contacting Adam.
scale bar = 500 nm