Temperature induced crossing in the optical bandgap of mono and bilayer MoS2 on SiO2

Park, Young S.; Chan, Christopher C. S.; Taylor, Robert A.; Kim, Yong-Chul; Kim, Nammee; Jo, Young‐Heon; Lee, Seung-Woong; Yang, Woochul; Im, Hyunsik; Lee, Geunsik

doi:10.1038/s41598-018-23788-3

Cited by 6 publications

(4 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…9(d) we compare our calculated temperaturedependent band gap of MoS 2 (green) with experimental data from Ref. [96] (black). To facilitate comparison we introduced a scissor correction of 0.34 eV to match the measured band gap at 4 K. This correction is similar to that obtained using GW and the Bethe-Salpeter equation (BSE) [97].…”

Section: Summary Of Procedures and Numerical Resultsmentioning

confidence: 96%

“…We show the results of the special displacement method (green circles) and experimental data from Ref. [96] (black triangles). The calculated band gaps were scissor-shifted by 0.34 eV to match the experimental value at 4 K. The straight line is the high-temperature limit and intercepts the T = 0 K axis at the clamped-ion band gap (1.93 eV, empty circle).…”

Section: Discussionmentioning

confidence: 99%

“…(d) Temperature dependence of the indirect band gap of monolayer MoS2 up to 400 K, evaluated using a 10×10×1 supercell. We show the results of the special displacement method (green circles) and experimental data from Ref [96]. (black triangles).…”

mentioning

confidence: 99%

See 2 more Smart Citations

Theory of the special displacement method for electronic structure calculations at finite temperature

Zacharias

Giustino

2020

Phys. Rev. Research

101

123

View full text Add to dashboard Cite

Calculations of electronic and optical properties of solids at finite temperature including electronphonon interactions and quantum zero-point renormalization have enjoyed considerable progress during the past few years. Among the emerging methodologies in this area, we recently proposed a new approach to compute optical spectra at finite temperature including phonon-assisted quantum processes via a single supercell calculation [Zacharias and Giustino, Phys. Rev. B 94, 075125 (2016)]. In the present work we considerably expand the scope of our previous theory starting from a compact reciprocal space formulation, and we demonstrate that this improved approach provides accurate temperature-dependent band structures in three-dimensional and two-dimensional materials, using a special set of atomic displacements in a single supercell calculation. We also demonstrate that our special displacement reproduces the thermal ellipsoids obtained from X-ray crystallography, and yields accurate thermal averages of the mean-square atomic displacements. At a more fundamental level, we show that the special displacement represents an exact single-point approximant of an imaginary-time Feynman's path integral for the lattice dynamics. This enhanced version of the special displacement method enables non-perturbative, robust, and straightforward ab initio calculations of the electronic and optical properties of solids at finite temperature, and can easily be used as a post-processing step to any electronic structure code. To illustrate the capabilities of this method, we investigate the temperature-dependent band structures and atomic displacement parameters of prototypical nonpolar and polar semiconductors and of a prototypical two-dimensional semiconductor, namely Si, GaAs, and monolayer MoS2, and we obtain excellent agreement with previous calculations and experiments. Given its simplicity and numerical stability, the present development is suited for high-throughput calculations of band structures, quasiparticle corrections, optical spectra, and transport coefficients at finite temperature.

show abstract

Section: Summary Of Procedures and Numerical Resultsmentioning

confidence: 96%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Theory of the special displacement method for electronic structure calculations at finite temperature

Zacharias

Giustino

2020

Phys. Rev. Research

101

123

View full text Add to dashboard Cite

show abstract

“…It has been established in many experimental and theoretical works [ 2 , 5 , 14 , 15 , 18 , 38 , 40 , 41 ] that MoS 2 remains an indirect semiconductor even when reduced to bilayers. Observation of the indirect-gap emission around 1.25 eV on 3 nm-thick MoS 2 ( Figure 3 ) has revealed that MoS 2 retains its indirect characteristics even when its thickness is reduced to just four layers.…”

Section: Resultsmentioning

confidence: 99%

Two-Channel Indirect-Gap Photoluminescence and Competition between the Conduction Band Valleys in Few-Layer MoS2

Bayramov,

Bagiyev,

Alizade

et al. 2023

Nanomaterials

View full text Add to dashboard Cite

MoS2 is a two-dimensional layered transition metal dichalcogenide with unique electronic and optical properties. The fabrication of ultrathin MoS2 is vitally important, since interlayer interactions in its ultrathin varieties will become thickness-dependent, providing thickness-governed tunability and diverse applications of those properties. Unlike with a number of studies that have reported detailed information on direct bandgap emission from MoS2 monolayers, reliable experimental evidence for thickness-induced evolution or transformation of the indirect bandgap remains scarce. Here, the sulfurization of MoO3 thin films with nominal thicknesses of 30 nm, 5 nm and 3 nm was performed. All sulfurized samples were examined at room temperature with spectroscopic ellipsometry and photoluminescence spectroscopy to obtain information about their dielectric function and edge emission spectra. This investigation unveiled an indirect-to-indirect crossover between the transitions, associated with two different Λ and K valleys of the MoS2 conduction band, by thinning its thickness down to a few layers.

show abstract

Temperature‐Dependent Electronic Ground‐State Charge Transfer in van der Waals Heterostructures

et al. 2021

View full text Add to dashboard Cite

A single layer of a 2D material may be insulating (e.g., hexagonal boron nitride), semiconducting (e.g., MoS 2 ), or conducting (e.g., graphene), and thus all electrical material properties required for the construction of an electronic or optoelectronic device are available in the monolayer limit. [3][4][5][6] Stacks of such mono layers are typically bound by weak van der Waals (vdW) interlayer interactions, and vdW heterostructures have emerged as prime candidates for realizing electronic and optoelectronic functions in the smallest possible volume. The type and efficiency of the functionality that can be achieved depends critically on the electronic energy level alignment across the heterostructure, [7] and substantial charge density rearrangement upon contact can occur, depending on the electronic structure of each component. Consequently, charge rearrangement and also charge transfer (CT) phenomena that define the electronic ground state of vdW heterostructures must be thoroughly understood Electronic charge rearrangement between components of a heterostructure is the fundamental principle to reach the electronic ground state. It is acknowledged that the density of state distribution of the components governs the amount of charge transfer, but a notable dependence on temperature is not yet considered, particularly for weakly interacting systems. Here, it is experimentally observed that the amount of ground-state charge transfer in a van der Waals heterostructure formed by monolayer MoS 2 sandwiched between graphite and a molecular electron acceptor layer increases by a factor of 3 when going from 7 K to room temperature. State-of-the-art electronic structure calculations of the full heterostructure that accounts for nuclear thermal fluctuations reveal intracomponent electron-phonon coupling and intercomponent electronic coupling as the key factors determining the amount of charge transfer. This conclusion is rationalized by a model applicable to multicomponent van der Waals heterostructures.

show abstract

Temperature induced crossing in the optical bandgap of mono and bilayer MoS2 on SiO2

Cited by 6 publications

References 28 publications

Theory of the special displacement method for electronic structure calculations at finite temperature

Theory of the special displacement method for electronic structure calculations at finite temperature

Two-Channel Indirect-Gap Photoluminescence and Competition between the Conduction Band Valleys in Few-Layer MoS2

Temperature‐Dependent Electronic Ground‐State Charge Transfer in van der Waals Heterostructures

Contact Info

Product

Resources

About