AUTHORS:

Agrawal A.V., Polyakov A.Y., Eriksson J., Antosiewicz T.J., Shegai T.O.

ABSTRACT:

Ambient humidity poses a significant challenge in the development of practical room-temperature NO₂ gas sensors. Herein, atomically precise zigzag edges are employed in multilayer MoS₂, fabricated using electron beam lithography and anisotropic wet etching, to achieve highly sensitive and selective gas-sensing performance, that is, humidity-tolerant at elevated temperatures and humidity-enhanced at room temperature under ultraviolet illumination. Notably, exposure to 2.5 parts per billion (ppb) NO₂ at 70% relative humidity under ultraviolet illumination and at room temperature resulted in a 33-fold increase in response and a 6-fold faster recovery compared to 0% relative humidity, leading to response values exceeding 1100%. The optimized samples demonstrate a theoretical detection limit ranging from 4 to 400 parts per trillion (ppt) NO₂. The enhanced NO₂ sensing capabilities of MoS₂ edges have been further confirmed through first-principles calculations. This study expands the applications of nanostructured MoS₂ and highlights its potential for detecting NO₂ at sub-ppb levels in complex scenarios, such as high-humidity conditions.

Small Structures, 2025, vol. 6(4), art. 2400409, doi: 10.1002/sstr.202400409