Fujitsu Laboratories Ltd. has unveiled what it believes to be the first highly sensitive gas sensor to use graphene technology.
The sensor operates on a new principle in which the gate part of the silicon transistor is replaced by graphene.
The development may pave the way for compact instruments that can measure specific gas components with speed and sensitivity in order to monitor atmospheric pollution or test for organic gases in a person's breath to detect disease.
The gas sensor can measure a few tens of parts per billion, or ppb, of ammonia, NH3, and less than 1 ppb of nitrogen dioxide, NO2, in a nitrogen environment. Its sensitivity to NO2 is reported to be an order of magnitude greater than conventional resistivity-based graphene sensors, at less than 1 ppb, and commercially available electrochemical sensors, which have sensitivity of over tens of ppb.
Fujitsu Labs, a unit of the $41-billion Japanese information and communication technology company Fujitsu Ltd., is developing ultrafast, low-power transistors and other devices, including high-sensitivity sensors, based on graphene, a two-dimensional sheet of carbon a mere one atom thick.
The material’s conductive properties make it a potential replacement for conventional semiconductors in transistors, or very-large-scale integration, VLSI, circuitry, which are reaching the limits of miniaturization.
The Fujitsu sensor reportedly is compact, with a detection area of a few hundred micrometers, but could be made even smaller. Sensitivity is greater than existing technologies, and because its mechanism does not rely on chemical reactions, the sensor returns to its original state through methods such as applying heat to the device. This sensor also could be used in a compact device that could measure NO2 almost anywhere, in real time.
The company says it aims to put it into practical use as an environmental sensor after verifying its characteristics and studying its durability. Fujitsu also plans to find ways to detect gases other than NO2 and ammonia by combining graphene with other molecules.
By pairing this sensor with another announced in April that can measure ammonia with a high degree of sensitivity, Fujitsu intends to develop a highly sensitive and portable sensor that can be used as conveniently as a thermometer to measure gases in human breath for early detection of diseases.