17 / 2016-08-18 10:28:05

Few layers WS2 thin film for room temperature high performance humidity sensor

11158,11159,11160

Humidity sensors have wide applications in industry, agriculture, environment monitoring and medical service. The current commercial available electronic hygrometers are mostly either based on semiconducting powders or polymers coated on ceramic heating stage. Those humidity sensors must be heated to keep their sensitivity. In addition, the polymer hygrometer can hardly work in direct current (DC) mode for long time duration, which results in complexity of the sensing system. Recently, atomically thin transition metal dichalcogenides (TMDCs) have been proposed as sensing components for detecting many kinds of chemical species thanks to their extremely high surface-to-volume ratio. Here, we report that by simply sulfurizing an ultrathin W film in a furnace tube, polycrystalline few layers WS2 thin film with high humidity sensing performance can be obtained. Furthermore, a flexible humidity sensor was fabricated by transferring the as-synthesized WS2 thin film onto a polydimethylsiloxane (PDMS) substrate. This flexible humidity sensor shows nearly repeatable sensing performance both on flat and bent states. We believe the humidity senor based on few layer WS2 may not only can be used for silicon-integrated smart chips but also have great potential for e-skin application.