Identification of individual and few layers of WS2 using Raman Spectroscopy

Ayse Berkdemir; Humberto R. Gutiérrez; Andrés R. Botello-Méndez; Néstor Perea-López; Ana Laura Elías; Chen Ing Chia; Bei Wang; Vincent H. Crespi; Florentino López-Urías; Jean Christophe Charlier; Humberto Terrones; Mauricio Terrones

doi:10.1038/srep01755

Identification of individual and few layers of WS₂ using Raman Spectroscopy

Ayse Berkdemir
, Humberto R. Gutiérrez
, Andrés R. Botello-Méndez
, Néstor Perea-López
, Ana Laura Elías
, Chen Ing Chia
, Bei Wang
, Vincent H. Crespi
, Florentino López-Urías
, Jean Christophe Charlier
, Humberto Terrones
, Mauricio Terrones^*

^*Corresponding author for this work

Research output: Contribution to journal › Article › Academic › peer-review

Abstract

The Raman scattering of single- and few-layered WS₂ is studied as a function of the number of S-W-S layers and the excitation wavelength in the visible range (488, 514 and 647 nm). For the three excitation wavelengths used in this study, the frequency of the A 1g (Γ) phonon mode monotonically decreases with the number of layers. For single-layer WS₂, the 514.5 nm laser excitation generates a second-order Raman resonance involving the longitudinal acoustic mode (LA(M)). This resonance results from a coupling between the electronic band structure and lattice vibrations. First-principles calculations were used to determine the electronic and phonon band structures of single-layer and bulk WS₂. The reduced intensity of the 2LA mode was then computed, as a function of the laser wavelength, from the fourth-order Fermi golden rule. Our observations establish an unambiguous and nondestructive Raman fingerprint for identifying single- and few-layered WS₂ films.

Original language	English
Article number	1755
Journal	Scientific Reports
Volume	3
DOIs	https://doi.org/10.1038/srep01755
Publication status	Published - 2013
Externally published	Yes

Funding

M.T., H.R.G., A.L.E. and V.H.C. acknowledge funding from the U. S. Army Research Office MURI grant W911NF-11-1-0362. This research was partially supported by the Materials Simulation Center of the Materials Research Institute, the Research Computing and Cyberinfrastructure unit of Information Technology Services. MT acknowledges JST-Japan for funding the Research Center for Exotic NanoCarbons, under the Japanese regional Innovation Strategy Program by the Excellence. M.T. and V.H.C. also acknowledge support from a Penn State Center for Nanoscale Science Seed grant on 2-D Layered Materials (DMR-0820404). This publication was also supported by the Pennsylvania State University Materials Research Institute Nanofabrication Lab and the National Science Foundation Cooperative Agreement No. ECS-0335765. Electron microscopy characterization facilities within the Materials Research Institute at the Pennsylvania State University were also used for this research. A.R.B.M. and J.-C.C. acknowledge financial support from the F.R.S.-FNRS of Belgium. This research is directly connected to the ARC on « Graphene StressTronics » sponsored by the Communauté Française de Belgique.

Funders	Funder number
F.R.S.-FNRS of Belgium
JST-Japan
Materials Simulation Center of the Materials Research Institute
Penn State Center for Nanoscale Science Seed	DMR-0820404
U. S. Army Research Office MURI	W911NF-11-1-0362
National Science Foundation
Directorate for Engineering	0335765
Pennsylvania State University

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10.1038/srep01755

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@article{0529f34a70e14938a0eb6f8f20707993,

title = "Identification of individual and few layers of WS2 using Raman Spectroscopy",

abstract = "The Raman scattering of single- and few-layered WS2 is studied as a function of the number of S-W-S layers and the excitation wavelength in the visible range (488, 514 and 647 nm). For the three excitation wavelengths used in this study, the frequency of the A 1g (Γ) phonon mode monotonically decreases with the number of layers. For single-layer WS2, the 514.5 nm laser excitation generates a second-order Raman resonance involving the longitudinal acoustic mode (LA(M)). This resonance results from a coupling between the electronic band structure and lattice vibrations. First-principles calculations were used to determine the electronic and phonon band structures of single-layer and bulk WS2. The reduced intensity of the 2LA mode was then computed, as a function of the laser wavelength, from the fourth-order Fermi golden rule. Our observations establish an unambiguous and nondestructive Raman fingerprint for identifying single- and few-layered WS2 films.",

author = "Ayse Berkdemir and Guti{\'e}rrez, \{Humberto R.\} and Botello-M{\'e}ndez, \{Andr{\'e}s R.\} and N{\'e}stor Perea-L{\'o}pez and El{\'i}as, \{Ana Laura\} and Chia, \{Chen Ing\} and Bei Wang and Crespi, \{Vincent H.\} and Florentino L{\'o}pez-Ur{\'i}as and Charlier, \{Jean Christophe\} and Humberto Terrones and Mauricio Terrones",

year = "2013",

doi = "10.1038/srep01755",

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volume = "3",

journal = "Scientific Reports",

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T1 - Identification of individual and few layers of WS2 using Raman Spectroscopy

AU - Berkdemir, Ayse

AU - Gutiérrez, Humberto R.

AU - Botello-Méndez, Andrés R.

AU - Perea-López, Néstor

AU - Elías, Ana Laura

AU - Chia, Chen Ing

AU - Wang, Bei

AU - Crespi, Vincent H.

AU - López-Urías, Florentino

AU - Charlier, Jean Christophe

AU - Terrones, Humberto

AU - Terrones, Mauricio

PY - 2013

Y1 - 2013

N2 - The Raman scattering of single- and few-layered WS2 is studied as a function of the number of S-W-S layers and the excitation wavelength in the visible range (488, 514 and 647 nm). For the three excitation wavelengths used in this study, the frequency of the A 1g (Γ) phonon mode monotonically decreases with the number of layers. For single-layer WS2, the 514.5 nm laser excitation generates a second-order Raman resonance involving the longitudinal acoustic mode (LA(M)). This resonance results from a coupling between the electronic band structure and lattice vibrations. First-principles calculations were used to determine the electronic and phonon band structures of single-layer and bulk WS2. The reduced intensity of the 2LA mode was then computed, as a function of the laser wavelength, from the fourth-order Fermi golden rule. Our observations establish an unambiguous and nondestructive Raman fingerprint for identifying single- and few-layered WS2 films.

AB - The Raman scattering of single- and few-layered WS2 is studied as a function of the number of S-W-S layers and the excitation wavelength in the visible range (488, 514 and 647 nm). For the three excitation wavelengths used in this study, the frequency of the A 1g (Γ) phonon mode monotonically decreases with the number of layers. For single-layer WS2, the 514.5 nm laser excitation generates a second-order Raman resonance involving the longitudinal acoustic mode (LA(M)). This resonance results from a coupling between the electronic band structure and lattice vibrations. First-principles calculations were used to determine the electronic and phonon band structures of single-layer and bulk WS2. The reduced intensity of the 2LA mode was then computed, as a function of the laser wavelength, from the fourth-order Fermi golden rule. Our observations establish an unambiguous and nondestructive Raman fingerprint for identifying single- and few-layered WS2 films.

UR - https://www.scopus.com/pages/publications/84877738846

U2 - 10.1038/srep01755

DO - 10.1038/srep01755

M3 - Article

AN - SCOPUS:84877738846

SN - 2045-2322

VL - 3

JO - Scientific Reports

JF - Scientific Reports

M1 - 1755

ER -

Identification of individual and few layers of WS₂ using Raman Spectroscopy

Abstract

Funding

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