Ionic liquid-gated graphene FET array with enhanced selectivity for electronic nose

We report the selectivity enhancement of the graphene gas sensor using ionic liquids (ILs). Because the gas absorbability and selectivity of the IL depends on the types of its anion and cation, the graphene sensors covered with different ILs have different gas responses. We fabricated the IL-gated graphene field-effect transistors (ILGFETs) and assembled three ILGFEiodineTs with three kinds of ILs into an ILGFET array. Their responses to ammonia, hydrogen peroxide, and iodine were measured. The ILGFET with an IL ([EMIM][BF₄]) was more selective for ammonia and iodine and less selective for iodine than that with another IL ([EMIM][TFSI]). The response patterns obtained using the ILGFET array indicated the feasibility of the graphene electronic nose.