Flexible In2Se3 sensor for chemiresistive NO2 detection at room temperature

Piezoelectric semiconductors offer tremendous opportunity in nanosensors. In this work, we demonstrate the fabrication of a flexible gas sensor based on few-layer In2Se3 nanosheets synthesized by CVD, which exhibits high sensitivity to NO2 with fast response/recovery speed (3/40 s) at room temperature (RT) and a low detection limit of 71 ppb. We further investigated the piezoelectric effect by mechanical deformation on the sensor properties. When the deformation increased from 0.18% to 0.98%, the sensor response showed a remarkable increase and reached the maximum at 0.31%, then decreased. The improved sensing property can be ascribed to coupled effect of piezoelectricity and adsorption-induced charge transfer in the In2Se3 device. Our work opens up a way to develop new piezoelectric chemical sensors.