Interface Engineering-Driven Room-Temperature Ultralow Gas Sensors with Elucidating Sensing Performance of Heterostructure Transition Metal Dichalcogenide Thin Films.

In this report, we investigate the room-temperature gas sensing performance of heterostructure transition metal dichalcogenide (MoSe/MoS, WS/MoS, and WSe/MoS) 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, NH, H, CO, and HS 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/MoS-based sensor was found to have an excellent selectivity toward NO 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.