Monolayer GeS as a potential candidate for NO2 gas sensors and capturers

The gas sensing properties of single-layer GeS have been studied by performing density functional theory (DFT) calculations, and the present results demonstrate that monolayer GeS exhibits high selectivity and sensitivity toward NO2 molecules and short recovery time, coupled with a strong anisotropic transport feature. Moreover, applying biaxial strains and electric fields could effectively modulate the capture and release of gaseous NO2. Further calculations indicate that oxygen atoms and water molecules decorated on GeS hardly affect the superb selectivity toward NO2 against the other gases. The presence of an S-vacancy on the GeS monolayer greatly promotes the adsorption of NO2, facilitating molecular dissociation. The underlying mechanism is also elaborated at the level of electronic structures. The present findings make GeS monolayers potential materials for NO2 gas sensors and capturers in future applications.