NO gas adsorption properties of MoS₂ from monolayer to trilayer: a first-principles study

Abstract

The NO gas adsorption properties of the monolayer, bilayer and trilayer MoS2 has been studied based on the first-principles calculation. The interaction between NO and MoS2 layers is weak physical adsorption, which is evidenced by the large distance (>3 Å), small adsorption energies (<0.9 eV) and deformation electron density. Moreover, the effect of the NO adsorption on the charge transfer and the electronic properties are also discussed. For all the NO adsorption cases, 0.04 e charge transfer exists by Mulliken/Hirshfeld analysis and and the charge density difference between NO molecular and MoS2 layers. The NO adsorption can obviously induces new impurity states at about 0.5 eV in the band gap that can lead to the change of the transport properties of the MoS2 layers and then it could detect the NO gas. We also performed semi-quantitatively theoretical analysis from the carrier concentration n and carrier mobility μ to obtain the effect of the NO adsorption on electrical conductivity. Our results provide a theoretical basis for the application of MoS2 layers as gas sensors for important NO polluting gases in air.

Defect mediated visible light induced photocatalytic activity of Co3O4 nanoparticle decorated MoS2 nanoflower: A combined experimental and theoretical study

“…The smaller band gap corresponds to a higher carrier concentration and, consequently, high conductivity. MoS 2 @Co 3 O 4 nanocomposite's band structure shifts in the direction of least energy, which also suggests an exothermic process [ 37 ]. Additionally, defect states are created near the fermi level, which significantly changes the transport properties.…”

“…At the same time, the DFT semi-core pseudopotential (DSSP) method was under consideration to deal with the influence of core electron relativity. The convergence criteria of geometry optimizations were set to 5 × 10 −3 A for displacement and 4 × 10 −3 Ha/Å for force, respectively [ 37 ]. A global orbital cut-off radius of 5.0 and a smearing value of 0.005 Ha for orbital occupancy were applied where the self-consistent field (SCF) convergence accuracy was 1 × 10 −5 Ha.…”

“…The spin polarization effect was not considered in all the calculations. The Brillouin zone is sampled with a grid parameter 5 × 5 × 1 k points by the Monkhorst-Pack scheme method [ 37 ]. Our measured energy gap of the MoS 2 single layer was 1.83eV with a definite tolerance range compared with other theoretical results [ 38 ].…”

Application of Two-Dimensional Materials towards CMOS-Integrated Gas Sensors

“…It should also be noted that the adsorption of gas molecules on the ML MoS 2 surface results in a change in its band structure, depicted in Figure 17 a,b in the case of NO adsorption, from [ 201 ]. The adsorbed NO introduces additional energy states at 0.5 eV, giving rise to a significant upward shift in the Fermi level.…”

“…The Fermi energy is set at 0 eV. (Reprinted (adapted) with permission from Wang et al [ 201 ], CC-BY 4.0).…”