Improved gas sensing properties of copper-doped MoSe₂ monolayers: a first-principles study on CO₂ and NO₂ adsorption

Abstract This paper investigates the impact of copper (Cu)-doped MoSe 2 monolayer (ML) on gas sensing properties. The adsorption behaviour of CO 2 and NO 2 gas molecules on Cu-doped MoSe 2 ML is reported and various sensing and electronic parameters such as adsorption energy, charge transfer and recovery time, are computed to delineate the adsorption characteristics and gas sensitivity. In our study, the doped Cu-atom in Se vacant MoSe 2 ML shows the adsorption energies to be −1.32 eV (O-orient) and −1.72 eV (C-orient), for CO 2 , while for NO 2 , they are −0.879 eV (O-orient) and −1.06 eV (N-orient), respectively. The negative formation energy of −6.62 eV shows the electronic stability of Cu-doped MoSe 2 ML and thermal stability, demonstrated by the molecular dynamics study through the Nose-Vervlet Thermostat (NVT) algorithm. Also, significant changes are observed in electronic conductivity and work function upon adsorbed Cu-MoSe 2 ML. Lastly, these outcomes illustrate that Cu doping amplifies the capture ability of MoSe 2 ML towards gas molecules, fostering improved electron interaction between the substrate surface and gas molecules, consequently enhancing its gas sensing ability.