Figure 7.

(a) Schematic of the device fabrication process. Humidity sensing properties of the WS₂ film on the SiO₂/Si substrate. (b) Current–voltage (I–V) characteristics in different relative humidities. Inset: Image of a rigid WS₂ sensor connected to the sample stage by wire bonding. (c) Response of the sensor at different relative humidities (RHs). (d) Time-dependent response current of three cycles of humidity switching between the low RH level (35%) and high RH level (40%). (e) Time-dependent response current with a fingertip vertically approaching and retracting away from the device surface at different distances. The RH of the test environment is about 40%. The RH near the finger is about 43%. Reprinted with permission from Ref. [72]. Copyright 2017 Royal Society of Chemistry.