Flexible Gas Sensor Based on Molybdenum Telluride/Molybdenum Disulfide Heterostructure

As the fast development of internet of things (IoT), the demand for gas sensors have increased considerably due to its broad applications in various fields, especially for the wearable environmental and health monitoring purposes. Traditional gas sensors are usually rigid and bulky, which can be hardly developed as wearable devices. In contrast, layered 2-D materials have large surface-to-volume ratio and excellent mechanical flexibility, making them one of the excellent materials to develop flexible gas sensors. In this work, we proposed a flexible gas sensor based on the MoS2/MoTe2 heterostructure. By depositing two pairs of electrodes, this heterostructure was designed to consist of three independent devices of MoS2 FET, MoTe2 FET, and MoS2/MoTe2 p-n junction, which showed distinct gas responses from each other. Therefore, it is possible for the heterostructure to distinguish different gas analytes by monitoring the response patterns of the three independent devices. The heterostructure was first fabricated on the rigid substrate of SiO2/Si, which successfully distinguished six gas analytes which are all potential disease-related biomarkers in human breath. Then, the heterostructure was fabricated on the flexible PI substrate, which can distinguish acetone and heptanone under various bending conditions. This work demonstrated the great promise of 2-D materials for wearable gas sensors.