Fig. 3
From: Free radical sensors based on inner-cutting graphene field-effect transistors
The field-effect transistor (FET) sensor with Cd2+, Zn2+, and Mg2+ as the indicator. a Real-time electrical responses of a graphene/Au/Cys-PP-metal ion FET device (modified in 10−4 M Cd2+, Zn2+, or Mg2+) upon successive addition of 10−9 M •OH. The inset shows the FET device with interdigital electrodes. b Liquid gate transfer curves (Vds = 50 mV) of a graphene/Au/Cys-PP-Zn2+ FET device (modified in 10−4 M Zn2+) before and after addition of 2 × 10−4, 4 × 10−4, 6 × 10−4, and 8 × 10−4 M •OH, when Vlg varies from −100 to 500 mV. c Real-time response upon various concentrations of •OH (from 10−9 to 10−4 M) for the graphene/Au/Cys-PP-Zn2+ FET device (modified in 10−4 M Zn2+). d The electrical responses versus the •OH concentration for the graphene/Au/Cys-PP-Zn2+ FET device (modified in 10−4 M Zn2+). The scale bar in a is 200 μm. The error bars are defined by the standard deviation of the results from three parallel experiments
