Intrinsic pH sensitivity of graphene field-effect transistors

Summary form only given. Intrinsic pH sensitivity of graphene field-effect transistors (FETs) were investigated. To free from defects and dislocations on the graphene surface, high-quality graphene film synthesized on a SiC substrate were used. And to remove other ions' influences, pH-adjusted phosphate-buffered solutions were prepared. In addition, a resist-free device fabrication, which was air plasma etching with a stencil mask, was carried out to reduce the residue effect. No shift of the transfer characteristics were observed with changing pH values. These results indicate that graphene film without any defects and dislocations does not bind to hydrogen ions or hydroxide ions.