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초록

The incomplete recovery of TMD gas sensors hinders their reliability and scalability. [ The leading cause of incomplete recovery is the strong chemisorpt ion of gas analytes, such as defects or grain boundaries on the active surface of 2D TMDs. [ Here in, we demonstrate an improvement in the recovery rate of TMD gas sensors by selectively passivating the TMD surface defects or vacancies with Al 2 O 3 via atom ic layer deposition. Scanning electron microscopy analysis confirms that the nucleation and growth of atomic layer deposited Al 2 O 3 occur along the grain boundaries and defects of the 2D MoS 2 and WS 2 , not covering the inert basal plane. In addition, the Ram an, photoluminescence , and X ray photoelectron spectroscopy data show lower surface defect densities and a slight n doping effect of Al 2 O 3 . This unique selectively defect passivated TMD gas sensor show s a 400 % response toward 10 ppm of NO 2 , along with an increase in the recovery rate from 74 to 96 %, even at room temperature, as the number of atomic layer deposition cycles increases. Also, the recovery rate of NH 3 , a reducing gas, shows an increase of more than 30 %. Thus, the method proposed here is a pro mising strategy for improving the recovery rate of 2D TMD gas sensors.