Exploring on the possibility of GeS used as small-molecule gases sensing

The adsorption of small-molecule gases (NO 2 , SO 2 , NO, H 2 , N 2 , O 2 , CO, CO 2 , H 2 O, H 2 S, and NH 3 ) on GeS was studied using first-principles density functional theory (DFT). The study revealed that, among the small-molecule gases, NO 2 , SO 2, and NO present the highest adsorption energies of 0.746 eV, 0.466 eV, and 0.412 eV, respectively. Moreover, the monolayer GeS transforms from a non-magnetic state to a magnetic state with a magnetic moment of 1 μ_B after NO 2 or NO adsorptions, resulting in significant changes in the electronic band structures. Especially, for the NO 2 adsorption system, exhibited exceptional adsorption density and an I – V curve shift demonstrate that GeS has high selectivity for sensing NO 2 gas. Therefore, our research results indicate that GeS is a promising candidate material for NO 2 gas sensing.