Band valley flattening and exciton appearance/disappearance under isotropic strain in monolayer WS2

Quang-Huy, Tran; Tran, Thi Nhan; Theu, Luong Thi; Ngo, V. Thanh; Phung, Thi Viet Bac; Dinh, Van An

doi:10.1140/epjp/s13360-022-03537-2

Cited by 1 publication

(2 citation statements)

References 43 publications

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“…E vac and E f stand for the vacuum level and Fermi energy, respectively. Work function of MoS 2 and WS 2 monolayers before adsorption is 5.78 and 5.908 eV, respectively, in good agreement with works [27], [22]. When exposed to methanal molecule, the monolayers of MoS 2 and WS 2 have the calculated work functions of 6.136 and 5.867 eV, respectively.…”

Section: B Adsorption Energysupporting

confidence: 80%

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Adsorption behavior of formaldehyde gas on two-dimensional semiconductor monolayers MS₂ (M=W, Mo)

Theu Luong,

Huy Tran,

Nhan Tran

et al. 2024

J. Phys.: Conf. Ser.

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Detecting methanal molecule, an indoor air pollutant and potential carcinogen, is crucial for safeguarding human health, ensuring occupational safety, and maintaining environmental quality. In this study, density functional theory calculations have been performed to explore the adsorption behavior of formaldehyde (methanal) gas on the surface of two-dimensional semiconductor monolayers MS2 (M=W, Mo). Using the Computational DFT-based Nanoscope tool, we compute binding energies and determine configurations at global minimum energy of molecule adsorbed monolayer MS2. Five nonlocal van der Waals functionals; revPBE-vdW, optPBE-vdW, vdW-DF2, optB88-vdW, and optB86b-vdW are used to compute the adsorption energy profiles. The calculated results show that: (i) the optPBE-vdW functional products the largest adsorption energy magnitude, (ii) Methanal molecule exhibits physical adsorption on both MoS2 and WS2 materials (iii) Adsorption of methanal molecules may enhance the electrical conductivity of MoS2 and WS2 upon the electron donation to molecule by substrates. The adsorption energy magnitude, bandgap reduction, and charge transfer of the methanal-MoS2 adsorption system are respectively 1.04, 1.27, and 1.47 times larger than those of the methanal-WS2 adsorption system, while the diffusion barrier energy is 0.25 times smaller. These characteristic adsorption parameters imply that methanal exhibits higher sensitivity to the MoS2 substrate. This study also provides an in-depth discussion regarding the interaction between methanal and the MS2 substrate, focusing on aspects of relaxed geometrical structures, potential energy surface, adsorption energy, response length, recovery time, work function, charge transfer, density of states, and energy band structure.

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Section: B Adsorption Energysupporting

confidence: 80%

“…In its monolayer form, MS 2 has a direct bandgap at the K points in the Brillouin zone. The valence band maximum (VBM) and conduction band maximum (CBM) are typically located at the K [29], [22]. After adsorption, the VBM and CBM are still located at the K point.…”

Section: Charge Transfermentioning

confidence: 99%

Adsorption behavior of formaldehyde gas on two-dimensional semiconductor monolayers MS₂ (M=W, Mo)

Theu Luong,

Huy Tran,

Nhan Tran

et al. 2024

J. Phys.: Conf. Ser.

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show abstract

Band valley flattening and exciton appearance/disappearance under isotropic strain in monolayer WS2

Cited by 1 publication

References 43 publications

Adsorption behavior of formaldehyde gas on two-dimensional semiconductor monolayers MS₂ (M=W, Mo)

Adsorption behavior of formaldehyde gas on two-dimensional semiconductor monolayers MS₂ (M=W, Mo)

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Band valley flattening and exciton appearance/disappearance under isotropic strain in monolayer WS2

Cited by 1 publication

References 43 publications

Adsorption behavior of formaldehyde gas on two-dimensional semiconductor monolayers MS2 (M=W, Mo)

Adsorption behavior of formaldehyde gas on two-dimensional semiconductor monolayers MS2 (M=W, Mo)

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Adsorption behavior of formaldehyde gas on two-dimensional semiconductor monolayers MS₂ (M=W, Mo)

Adsorption behavior of formaldehyde gas on two-dimensional semiconductor monolayers MS₂ (M=W, Mo)