Nanosensors based on graphene inter-layer electronic properties: Sensing mechanism and selectivity

Graphene-based nanosensors with inter-layer structures were built and tested as gas sensors in response to ethanol and water molecules, and were compared with intra-layer nanosensors built on mono-layer and bi-layer graphenes. Ethanol and water molecules were chosen because they act differently as donors and acceptors to graphenes. The results show that the sensitivities of the inter-layer graphene nanosensors were over two times higher than the ones based on the mono-layer and bi-layer graphenes under the same experimental conditions. Strong suppression of the tunneling current through the two stacked graphene layers was observed, which is mainly caused by the reconstruction of the microscopic corrugation due to the adsorption of gas molecules.