Fig. 3.
pH detection of suspended MoS2FET: (a) Schematic of protonation and deprotonation on HfO2 substrate. (b) ID-VLG curve of different pH concentration on the suspended MoS2 (subset: Linear graph of ID-VLG). (c) Sensitivity of pH in subthreshold, saturation, and linear regions from pH 5 to pH 7. (d) experimental threshold voltage of suspended MoS2 FET from pH 3 to pH 9 (Left-axis); experimental current corresponds to threshold voltage (Right-axis).