Selective Sensing of Individual Gases Using Graphene Devices

Graphene chemiresistors have enabled gas and vapor detection with high sensitivity. However, changes in graphene resistivity under the equilibrium gas exposure cannot be used to determine both the gas concentration and its type, making the sensing selectivity with resistive detection one of the key barriers to overcome. In this paper, we report on using low frequency noise to define the new characteristic parameters, which, in combination with the resistance changes, form unique gas signatures. The noise measurements can also be used in combination with evaluating “memory step” effect in graphene under gas exposure. The “memory step” is an abrupt change of the current near zero gate bias at elevated temperatures T > 500 K in graphene transistors. The “memory step” in graphene under gas exposure can be also used for high-temperature gas sensors, and is attractive for harsh-environment applications.