Nanowire based sensors offer improved detection of volatile organic compounds

The physicists claim the sensors could offer several advantages over today's commercial gas sensors, including low power room temperature operation and the ability to detect one or several compounds over a range of concentrations. In collaboration with George Mason University and the University of Maryland, researchers at the National Institute of Standards and Technology (NIST) developed a proof of concept for a gas sensor made of a single nanowire and metal oxide nanoclusters. These were chosen to react to a specific organic compound. The sensors were built using the same fabrication processes used for silicon computer chips, but on a much smaller scale. Despite their microscopic size, the nanowires and titanium dioxide nanoclusters had a high surface to volume ratio that made them extremely sensitive. "The electrical current flowing through our nanosensors was in the microamps range, while traditional sensors require milliamps," explained NIST's Abhishek Motayed. "This meant we were sensing with a lot less power and energy. The nanosensors also offered greater reliability and smaller size. They're so small that you can put them anywhere." While the team's current experimental sensors are tuned to detect benzene as well as the similar volatile organic compounds toluene, ethylbenzene and xylene, its goal now is to build a device that includes an array of nanowires and various metal oxide nanoclusters for analysing mixtures of compounds. The researchers also plan to collaborate with other NIST teams to combine their ultraviolet light approach with heat induced nanowire sensing technologies.