Spectroscopic studies of atomic defects and bandgap renormalization in semiconducting monolayer transition metal dichalcogenides

Abstract

Assessing atomic defect states and their ramifications on the electronic properties of two dimensional van der Waals semiconducting transition metal dichalcogenides (SC TMDs) is the primary task to expedite multi disciplinary efforts in the promotion of next generation electrical and optical device applications utilizing these low dimensional materials. Here, with electron tunneling and optical spectroscopy measurements with density functional theory, we spectroscopically locate the midgap states from chalcogen atom vacancies in four representative monolayer SC TMDs (MoS2, WS2, MoSe2, WSe2), and carefully analyze the similarities and dissimilarities of the atomic defects in four distinctive materials regarding the physical origins of the missing chalcogen atoms and the implications to SC mTMD properties. In addition, we address both quasiparticle and optical energy gaps of the SC mTMD films and find out many body interactions significantly enlarge the quasiparticle energy gaps and excitonic binding energies, when the semiconducting monolayers are encapsulated by non interacting hexagonal boron nitride layers.

References in corpus (17)

• Observation of giant bandgap renormalization and excitonic effects in a monolayer transition metal dichalcogenide semiconductor
• Determination of band alignment in the single layer MoS2/WSe2 heterojunction
• Resonant tunnelling and negative differential conductance in graphene transistors
• Twist-controlled resonant tunnelling in graphene-boron nitride-graphene heterostructures
• Direct imaging of the band profile in single layer $Mo{S}_2$ on graphite: quasiparticle energy gap, metallic edge states and edge band bending
• Stability and dopability of native defects and group-V and -VII impurities in single-layer MoS2
• 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)
• Probing critical point energies of transition metal dichalcogenides: surprising indirect gap of single layer $SL-WS{e}_2$
• Large spin-orbit splitting of deep in-gap defect states of engineered sulfur vacancies in monolayer WS2
• First-principles theory of field-effect doping in transition-metal dichalcogenides: Structural properties, electronic structure, Hall coefficient, and electrical conductivity
• Defect-induced conductivity anisotropy in MoS2 monolayers
• Quasiparticle band-edge energy and band offsets of monolayer of molybdenum and tungsten chalcogenide
• Probing the spin-polarized electronic band structure in monolayer transition metal dichalcogenides by optical spectroscopy
• Tuning the valley and chiral quantum state of Dirac electrons in van der Waals heterostructures
• Accurate Gap Determination in Monolayer and Bilayer Graphene/h-BN Moire Superlattices
• Resonant tunnelling between the chiral Landau states of twisted graphene lattices
• Local Spectroscopic Characterization of Spin and Layer Polarization in WSe${}_2$

Cited by in corpus (8)

• Stability of charged sulfur vacancies in 2D and bulk MoS${}_2$ from plane-wave density functional theory with electrostatic corrections
• Chemical trends of deep levels in van der Waals semiconductors
• Room-temperature bipolar valleytronic transistor in MoS2/WSe2 heterostructures
• Two-dimensional plasmonic polarons in n-doped monolayer MoS2
• Direct probing of phonon mode specific electron-phonon scatterings in two-dimensional semiconductor transition metal dichalcogenides: Symmetry and Berry phase
• Low temperature carrier transport mechanism and photoconductivity of WSe2
• Methods for coherent optical Doppler orbitography
• Laser threshold magnetometry using green light absorption by diamond nitrogen vacancies in an external cavity laser