Interface Engineering-Driven Room-Temperature Ultralow Gas Sensors with Elucidating Sensing Performance of Heterostructure Transition Metal Dichalcogenide Thin Films
Ashwani Kumar, Amit Sanger, Sung Bum Kang, Ramesh Chandra
Abstract
In this report, we investigate the room-temperature gas sensing performance of heterostructure transition metal dichalcogenide (MoSe 2 /MoS 2, WS 2 /MoS 2, and WSe 2 /MoS 2 ) thin films grown over a silicon substrate using a pulse laser deposition technique. The sensing response of the aforementioned sensors to a low concentration range of NO 2, NH 3, H 2, CO, and H 2 S gases in air has been assessed at room temperature. The obtained results reveal that the heterojunctions of metal dichalcogenide show a drastic change in gas sensing performance compared to the monolayer thin films at room temperature. Nevertheless, the WSe 2 /MoS 2 -based sensor was found to have an excellent selectivity toward NO 2 gas with a particularly high sensitivity of 10 ppb. The sensing behavior is explained on the basis of a change in electrical resistance as well as carrier localization prospects. Favorably, by developing a heterojunction of diselenide and disulfide nanomaterials, one may find a simple way of improving the sensing capabilities of gas sensors at room temperature.