Methane-Mediated Vapor Transport Growth of Monolayer WSe<sub>2</sub> Crystals

The electrical and optical properties of semiconducting transition metal dichalcogenides (TMDs) can be tuned by controlling their composition and the number of layers they have. Among various TMDs, the monolayer WSe<sub>2</sub> has a direct bandgap of 1.65 eV and exhibits p-type or bipol...

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Main Authors: Hyeon-Sik Jang, Jae-Young Lim, Seog-Gyun Kang, Sang-Hwa Hyun, Sana Sandhu, Seok-Kyun Son, Jae-Hyun Lee, Dongmok Whang
Format: Article
Language:English
Published: MDPI AG 2019-11-01
Series:Nanomaterials
Subjects:
Online Access:https://www.mdpi.com/2079-4991/9/11/1642
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author Hyeon-Sik Jang
Jae-Young Lim
Seog-Gyun Kang
Sang-Hwa Hyun
Sana Sandhu
Seok-Kyun Son
Jae-Hyun Lee
Dongmok Whang
author_facet Hyeon-Sik Jang
Jae-Young Lim
Seog-Gyun Kang
Sang-Hwa Hyun
Sana Sandhu
Seok-Kyun Son
Jae-Hyun Lee
Dongmok Whang
author_sort Hyeon-Sik Jang
collection DOAJ
description The electrical and optical properties of semiconducting transition metal dichalcogenides (TMDs) can be tuned by controlling their composition and the number of layers they have. Among various TMDs, the monolayer WSe<sub>2</sub> has a direct bandgap of 1.65 eV and exhibits p-type or bipolar behavior, depending on the type of contact metal. Despite these promising properties, a lack of efficient large-area production methods for high-quality, uniform WSe<sub>2</sub> hinders its practical device applications. Various methods have been investigated for the synthesis of large-area monolayer WSe<sub>2</sub>, but the difficulty of precisely controlling solid-state TMD precursors (WO<sub>3</sub>, MoO<sub>3</sub>, Se, and S powders) is a major obstacle to the synthesis of uniform TMD layers. In this work, we outline our success in growing large-area, high-quality, monolayered WSe<sub>2</sub> by utilizing methane (CH<sub>4</sub>) gas with precisely controlled pressure as a promoter. When compared to the catalytic growth of monolayered WSe<sub>2</sub> without a gas-phase promoter, the catalytic growth of the monolayered WSe<sub>2</sub> with a CH<sub>4</sub> promoter reduced the nucleation density to 1/1000 and increased the grain size of monolayer WSe<sub>2</sub> up to 100 &#956;m. The significant improvement in the optical properties of the resulting WSe<sub>2</sub> indicates that CH<sub>4</sub> is a suitable candidate as a promoter for the synthesis of TMD materials, because it allows accurate gas control.
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spelling doaj.art-c4bf80f1d80f4511bffad89185ffedca2022-12-21T19:01:29ZengMDPI AGNanomaterials2079-49912019-11-01911164210.3390/nano9111642nano9111642Methane-Mediated Vapor Transport Growth of Monolayer WSe<sub>2</sub> CrystalsHyeon-Sik Jang0Jae-Young Lim1Seog-Gyun Kang2Sang-Hwa Hyun3Sana Sandhu4Seok-Kyun Son5Jae-Hyun Lee6Dongmok Whang7School of Advanced Materials Science and Engineering and SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University (SKKU), 2066, Seobu-Ro, Jangan-Gu, Suwon-Si, Gyeonggi-Do 16419, KoreaSchool of Advanced Materials Science and Engineering and SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University (SKKU), 2066, Seobu-Ro, Jangan-Gu, Suwon-Si, Gyeonggi-Do 16419, KoreaSchool of Advanced Materials Science and Engineering and SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University (SKKU), 2066, Seobu-Ro, Jangan-Gu, Suwon-Si, Gyeonggi-Do 16419, KoreaDepartment of Energy Systems Research and Department of Materials Science and Engineering, Ajou University, Suwon, Gyeonggi-Do 16499, KoreaSchool of Advanced Materials Science and Engineering and SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University (SKKU), 2066, Seobu-Ro, Jangan-Gu, Suwon-Si, Gyeonggi-Do 16419, KoreaDepartment of Physics, Mokpo National University, Muan-gun, Jeollanam-Do 58554, KoreaDepartment of Energy Systems Research and Department of Materials Science and Engineering, Ajou University, Suwon, Gyeonggi-Do 16499, KoreaSchool of Advanced Materials Science and Engineering and SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University (SKKU), 2066, Seobu-Ro, Jangan-Gu, Suwon-Si, Gyeonggi-Do 16419, KoreaThe electrical and optical properties of semiconducting transition metal dichalcogenides (TMDs) can be tuned by controlling their composition and the number of layers they have. Among various TMDs, the monolayer WSe<sub>2</sub> has a direct bandgap of 1.65 eV and exhibits p-type or bipolar behavior, depending on the type of contact metal. Despite these promising properties, a lack of efficient large-area production methods for high-quality, uniform WSe<sub>2</sub> hinders its practical device applications. Various methods have been investigated for the synthesis of large-area monolayer WSe<sub>2</sub>, but the difficulty of precisely controlling solid-state TMD precursors (WO<sub>3</sub>, MoO<sub>3</sub>, Se, and S powders) is a major obstacle to the synthesis of uniform TMD layers. In this work, we outline our success in growing large-area, high-quality, monolayered WSe<sub>2</sub> by utilizing methane (CH<sub>4</sub>) gas with precisely controlled pressure as a promoter. When compared to the catalytic growth of monolayered WSe<sub>2</sub> without a gas-phase promoter, the catalytic growth of the monolayered WSe<sub>2</sub> with a CH<sub>4</sub> promoter reduced the nucleation density to 1/1000 and increased the grain size of monolayer WSe<sub>2</sub> up to 100 &#956;m. The significant improvement in the optical properties of the resulting WSe<sub>2</sub> indicates that CH<sub>4</sub> is a suitable candidate as a promoter for the synthesis of TMD materials, because it allows accurate gas control.https://www.mdpi.com/2079-4991/9/11/1642tmd2d materialwse<sub>2</sub>monolayermethane promotersingle-crystal
spellingShingle Hyeon-Sik Jang
Jae-Young Lim
Seog-Gyun Kang
Sang-Hwa Hyun
Sana Sandhu
Seok-Kyun Son
Jae-Hyun Lee
Dongmok Whang
Methane-Mediated Vapor Transport Growth of Monolayer WSe<sub>2</sub> Crystals
Nanomaterials
tmd
2d material
wse<sub>2</sub>
monolayer
methane promoter
single-crystal
title Methane-Mediated Vapor Transport Growth of Monolayer WSe<sub>2</sub> Crystals
title_full Methane-Mediated Vapor Transport Growth of Monolayer WSe<sub>2</sub> Crystals
title_fullStr Methane-Mediated Vapor Transport Growth of Monolayer WSe<sub>2</sub> Crystals
title_full_unstemmed Methane-Mediated Vapor Transport Growth of Monolayer WSe<sub>2</sub> Crystals
title_short Methane-Mediated Vapor Transport Growth of Monolayer WSe<sub>2</sub> Crystals
title_sort methane mediated vapor transport growth of monolayer wse sub 2 sub crystals
topic tmd
2d material
wse<sub>2</sub>
monolayer
methane promoter
single-crystal
url https://www.mdpi.com/2079-4991/9/11/1642
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AT seoggyunkang methanemediatedvaportransportgrowthofmonolayerwsesub2subcrystals
AT sanghwahyun methanemediatedvaportransportgrowthofmonolayerwsesub2subcrystals
AT sanasandhu methanemediatedvaportransportgrowthofmonolayerwsesub2subcrystals
AT seokkyunson methanemediatedvaportransportgrowthofmonolayerwsesub2subcrystals
AT jaehyunlee methanemediatedvaportransportgrowthofmonolayerwsesub2subcrystals
AT dongmokwhang methanemediatedvaportransportgrowthofmonolayerwsesub2subcrystals