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Optical properties of large area WS2 grown by chemical vapor deposition

Optical properties of large area WS2 grown by chemical vapor deposition
Optical properties of large area WS2 grown by chemical vapor deposition
Transition metal dichalcogenides (TMDs) have attracted great attention for fundamental physics and possible application as optoelectronic devices [1-5]. Monolayers of TMDs are direct gap semiconductors with optical transition in inequivalent at K and K´ valleys and distinct optical selection rules due to the combination of spin-orbit interaction and broken inversion symmetry. As a consequence, optical excitation with circularly polarized light results in circularly polarized emission. Actually, recent studies for TMDs have evidenced important valley polarization degree and large excitonics effects as well particularly at lower temperatures [1-5].
In this work, we have investigated optical properties from large are a monolayers of WS2 on 295nm SiO2/Si grown by Van der Waals Epitaxy Chemical Vapor Deposition. Particularly , we have investigated polarization resolved photoluminescence (PL ) spectra for different light excitation intensities and temperatures using a 532 nm solid state laser. The s + and s - light excitation and detection were obtained using appropriate quarter wave plates and linear polarizers. At lower temperatures, we have observed different PL peaks for the WS2 monolayer. The temperature and laser power dependence of PL spectra evidences that the observed peaks are associated to neutral (X), charged excitons (X- ) and biexcitons (XX). Therefore, our results reveal important many -body interactions in atomically thin WS2 semiconductor.
Orsi Gordo, V.
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Covre, F.S.
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Galeti, H.V.A.
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Galvão Gobato, Y.
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Henini, M.
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Huang, C.C.
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Hewak, D.W.
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Orsi Gordo, V.
e828c348-5e69-4439-83b4-e2a2762ac5d9
Covre, F.S.
92c9d7bd-4562-4ad2-bac6-b9160ce31daa
Galeti, H.V.A.
53dd37a5-a0e7-4bd9-a445-d81c60504e11
Galvão Gobato, Y.
f3dbae96-8809-4ab4-84b5-927496586478
Henini, M.
dffaac17-caab-4a18-9eb6-c858d8bb1ed2
Huang, C.C.
825f7447-6d02-48f6-b95a-fa33da71f106
Hewak, D.W.
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Orsi Gordo, V., Covre, F.S., Galeti, H.V.A., Galvão Gobato, Y., Henini, M., Huang, C.C. and Hewak, D.W. (2017) Optical properties of large area WS2 grown by chemical vapor deposition. The winter school and workshop: New Frontiers in 2D materials: Approaches & Applications. 15 - 20 Jan 2017. 1 pp .

Record type: Conference or Workshop Item (Poster)

Abstract

Transition metal dichalcogenides (TMDs) have attracted great attention for fundamental physics and possible application as optoelectronic devices [1-5]. Monolayers of TMDs are direct gap semiconductors with optical transition in inequivalent at K and K´ valleys and distinct optical selection rules due to the combination of spin-orbit interaction and broken inversion symmetry. As a consequence, optical excitation with circularly polarized light results in circularly polarized emission. Actually, recent studies for TMDs have evidenced important valley polarization degree and large excitonics effects as well particularly at lower temperatures [1-5].
In this work, we have investigated optical properties from large are a monolayers of WS2 on 295nm SiO2/Si grown by Van der Waals Epitaxy Chemical Vapor Deposition. Particularly , we have investigated polarization resolved photoluminescence (PL ) spectra for different light excitation intensities and temperatures using a 532 nm solid state laser. The s + and s - light excitation and detection were obtained using appropriate quarter wave plates and linear polarizers. At lower temperatures, we have observed different PL peaks for the WS2 monolayer. The temperature and laser power dependence of PL spectra evidences that the observed peaks are associated to neutral (X), charged excitons (X- ) and biexcitons (XX). Therefore, our results reveal important many -body interactions in atomically thin WS2 semiconductor.

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Accepted/In Press date: 2016
e-pub ahead of print date: January 2017
Venue - Dates: The winter school and workshop: New Frontiers in 2D materials: Approaches & Applications, 2017-01-15 - 2017-01-20
Organisations: Optoelectronics Research Centre

Identifiers

Local EPrints ID: 404130
URI: http://eprints.soton.ac.uk/id/eprint/404130
PURE UUID: 99735f18-8742-4d08-ae30-7e797229eba5
ORCID for C.C. Huang: ORCID iD orcid.org/0000-0003-3471-2463
ORCID for D.W. Hewak: ORCID iD orcid.org/0000-0002-2093-5773

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Date deposited: 03 Jan 2017 09:23
Last modified: 18 Feb 2021 17:05

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Contributors

Author: V. Orsi Gordo
Author: F.S. Covre
Author: H.V.A. Galeti
Author: Y. Galvão Gobato
Author: M. Henini
Author: C.C. Huang ORCID iD
Author: D.W. Hewak ORCID iD

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