Ab initio study of adsorption behaviors of molecular adsorbates on the surface and at the edge of MoS2

摘要

Two dimensional (2D) semiconducting materials such as MoS2 have been actively investigated for their applications in nanodevices and gas sensors (or detectors). In this connection, we have investigated atomic and electronic structures of specific adsorbates on the surface of MoS2 and the edge of MoS2 armchair nanoribbons (ANRs) using density functional theory (DFT) calculations. Our calculations reveal that molecular adsorbates are well adsorbed at the edge of MoS2 than on the surface of MoS2. Despite the weak van der Waals (vdW) interaction between molecular adsorbates and MoS2 surface, paramagnetic molecules such as NO and NO2 induce the reduced band gap in MoS2 by making the states within the bandgap. On the other hand, adsorbed CO, NO, NO2, and O-2 at the edge of MoS2 ANRs have much influence on the band structures of MoS2 ANRs via dissociation into their constituent atoms, while adsorbed CO2, NH3, H-2, and N-2 at the edge of MoS2 ANRs do not much change the band structure of MoS2 ANRs due to no dissociation. Further, we identify that dissociated molecules rearrange the charge densities of MoS2 ANRs by making the states within the bandgap.