A Hybrid-DFT Study of Intrinsic Point Defects in $M{X}_2$ ($M$=Mo, W; $X$=S, Se) Monolayers

Abstract

Defects can strongly influence the electronic, optical and mechanical properties of 2D materials, making defect stability under different thermodynamic conditions crucial for material-property engineering. In this paper, we present an account of the structural and electronic characteristics of point defects in monolayer transition metal dichalcogenides $M{X}_2$ with $M$=Mo/W and $X$= S/Se, calculated with density-functional theory using the hybrid HSE06 exchange correlation functional including many-body dispersion corrections. For the simulation of charged defects, we employ a charge compensation scheme based on the virtual crystal approximation (VCA). We relate the stability and the electronic structure of charged vacancy defects in monolayer MoS${}_2$ to an explicit calculation of the S monovacancy in MoS${}_2$ supported on Au(111), and find convincing indication that the defect is negatively charged. Moreover, we show that the finite-temperature vibrational contributions to the free energy of defect formation can change the stability transition between adatoms and monovacancies by 300--400 K. Finally, we probe defect vibrational properties by calculating a tip-enhanced Raman scattering image of a vibrational mode of a MoS${}_2$ cluster with and without an S monovacancy.

References in corpus (16)

• Atomically thin MoS2: A new direct-gap semiconductor
• Valley polarization in MoS2 monolayers by optical pumping
• Observation of giant bandgap renormalization and excitonic effects in a monolayer transition metal dichalcogenide semiconductor
• Electrically Tunable Excitonic Light Emitting Diodes based on Monolayer WSe2 p-n Junctions
• Strong Photoluminescence Enhancement of MoS2 through Defect Engineering and Oxygen Bonding
• The virtual crystal approximation revisited: Application to dielectric and piezoelectric properties of perovskites
• Band structure of MoS_2, MoSe_2, and alpha-MoTe_2: Angle-resolved photoelectron spectroscopy and ab-initio calculations
• A systematic study of structural, electronic and optical properties of atomic scale defects in 2D transition metal dichalcogenides MX${}_2$ (M = Mo,W; X = S, Se, Te)
• Density-functional model for van der Waals interactions: Unifying many-body atomic approaches with nonlocal functionals
• Ab initio atomistic thermodynamics and statistical mechanics of surface properties and functions
• 103-Compound Band Structure Benchmark of Post-SCF Spin-Orbit Coupling Treatments in Density-Functional Theory
• Giant spin-orbit splitting of point defect states in monolayer WS${}_2$
• Substrate screening effects on the quasiparticle band gap and defect charge transition levels in MoS${}_2$
• Moiré structure of MoS${}_2$ on Au(111): Local structural and electronic properties
• Stability of charged sulfur vacancies in 2D and bulk MoS${}_2$ from plane-wave density functional theory with electrostatic corrections
• Band Bending and Valence Band Quantization at Line Defects in MoS${}_2$

Cited by in corpus (4)

• First-Principles Simulations of Tip Enhanced Raman Scattering Reveal Active Role of Substrate on High-Resolution Images
• Electronic and magnetic properties of single chalcogen vacancies in MoS${}_2$/Au(111)
• An atomic-scale perspective on individual thiol-terminated molecules anchored to single S vacancies in MoS${}_2$
• Radiative electronic bound states in the continuum from defects in semiconductors