Fig. 2

Characterization of electrical properties of pH sensors. (A) Photograph showing the moment for electrical measurement of DB EGTFTs. (B) Schematic configuration showing the cross-sectional structure and electrical connections of the DB EGTFTs. (C) Transfer characteristics of DB EGTFTs at VD = 0.5Â V with different back gate voltage (VBG), where pH is pinned at 7. Semiconductor parameters extraction of (D) gm and (E) SS by leveraging VBG from 0Â V to 40Â V; error bars denote a standard deviation for a total of 50 devices. (F) The VTH plots of DB EGTFTs (VD = 0.5Â V) against VBG. The dashed red line indicates a linear fitting from the experimental data. The error bars were calculated from three parallel experiments.