Fig. 1
From: Free radical sensors based on inner-cutting graphene field-effect transistors
Fabrication and characterization of a field-effect transistor (FET) sensor. a Schematic diagram of the device fabrication process. b Raman spectrum of a graphene film. c Field-emission scanning electron microscope images of the graphene film decorated with Au nanoparticles (step i). d–f X-ray photoelectron spectroscopic spectra of Au 4f7/2 and Au 4f5/2, S 2p, and N 1s for (step i) graphene/Au, (step ii) graphene/Au/Cys, (step iii) graphene/Au/Cys-PP, and (step v) graphene/Au/Cys-PP-Cd2+ after reaction with •OH. g Output characteristics of a graphene/Au/Cys-PP FET sensor (Vbg varies from 0 to −90 V). The scale bar in c is 200 nm
