Gas sensors based on graphene – Comparison of two different fabrication approaches
Graphene’s electronic properties are strongly affected by the adsorption of molecules making this material very attractive for gas sensing application. The present work investigates the use of graphene as gas sensing active layer. Herein, two different approaches to fabricate graphene conductometric sensors were persued: a mechanically exfoliated single graphene flake device and a thin film of chemically exfoliated graphene flakes device. First preliminary findings indicated the second approach as a promising and simple method to fabricate a graphene based chemiresistor. Electrical sensor characterizations towards NO2 and moisture are shown. Issues related to fabrication processes are also discussed.
Graphene is a monolayer of carbon atoms arranged in a two-dimensional honeycomb structure, and is the starting point for any material derived from carbon (fullerenes, nanotubes or graphite). Graphene’s electronic properties are strongly affected by the adsorption of molecules (1), a prerequisite for an optimal electrically based sensor. This sensitivity has two main origins. in one hand, the two-dimensional nature of graphene allows a total exposure of all its atoms to the adsorbing gas molecules, providing the greatest sensor area per unit volume (2). In the other hand, it has inherently low electrical noise due to the quality of its crystal lattice and again, to its two-dimensional nature, which tends to screen charge fluctuations more than one-