First-principles study of mechanical, electronic and optical properties of Janus structure in transition metal dichalcogenides
Journal
Applied Surface Science
Journal Volume
526
Start Page
146730
ISSN
01694332
Date Issued
2020
Author(s)
Abstract
Using first-principles calculations, we investigate mechanical, electronic and optical properties of so-called Janus structure for monolayer transition metal dichalcogenides (TMDs), MXY (M = Mo, W; X or Y = S, Se, Te; X ≠ Y), in which chalcogen atoms at both side of the TMDs are not the same elements. Our calculated results indicate that WSSe shows the highest stiffness and the most ideal strength among the Janus TMDs due to their strongest ionic bond. In the unstrain cases, WSeTe, WSSe and MoSeTe are direct-gap semiconductors, while MoSSe, MoSTe and WSTe are indirect-gap semiconductors. The energy band gaps of the Janus TMDs decrease with increasing of the tensile strain due to the coupling between the p and d orbitals of the X/Y and M atoms, respectively. Furthermore, the tensile strain effectively modulates the optical absorption of the Janus TMDs. For example, the optical absorption of MoSSe is three times stronger at a photon energy of 2.5 eV. The calculated results of Janus TMDs provide useful information for applications in nanoelecromechanical, optoelectronic, and photocatalyst devices.
Subjects
Density Functional Theory
Ideal Strength
Janus Transition Metal Dichalcogenides
Optical Absorption
Calculations
Energy Gap
Ionic Strength
Light Absorption
Optical Properties
Selenium Compounds
Semiconducting Tellurium Compounds
Tensile Strain
Transition Metals
Chalcogen Atoms
Direct-gap Semiconductor
Electronic And Optical Properties
First-principles Calculation
First-principles Study
Ideal Strength
Photo-catalyst Devices
Transition Metal Dichalcogenides
Semiconducting Selenium Compounds
Publisher
Elsevier B.V.
Type
journal article