A first-principles study of Cl2, PH3, AsH3, BBr3 and SF4 gas adsorption on MoS2 monolayer with S and Mo vacancy

The intrinsic influence of gas sensing nature of S vacancy (V_S) and Mo vacancy (V_Mo) MoS₂ monolayer plays an important vital role for sensing highly toxic gases. A systematic study was carried out to act its ability to be a gas sensor, which can be benefited from its high surface to volume ratio similar to graphene. The highly toxic gas molecules such as Cl₂, PH₃, AsH₃, BBr₃ and SF₄ was selected to examine the affinity with V_S and V_Mo MoS₂ monolayer based on first principle calculations. To explore the sensing capacity and electronic property of V_S and V_Mo MoS₂ monolayer the geometrical structures, adsorption energy, adsorption distance, charge transfer and density of states were analyzed and discussed. The results indicate that all the gas molecules are allowed to adsorb on V_S and V_Mo MoS₂ monolayer through Van Der Waals interaction. Among all these gases, PH₃ adsorption on V_Mo MoS₂ monolayer exhibits relatively high adsorption energy of −1.8082 eV and charge transfer of −0.56 e, followed by the SF₄ on V_S and V_Mo MoS₂ monolayer showing enhanced adsorption energy of 0.9366 eV and −0.8052 eV and charge transfer of 0.029 e and 0.064 e respectively. PH₃ and BBr₃ adsorption on V_Mo MoS₂ monolayer shows more change in the conductivity when compared to other gas molecules. Thus, V_S and V_MO MoS₂ monolayer are producing beneficial results for sensing PH₃, BBr₃ and SF₄ gas molecules than Cl₂ and AsH₃.