Disentangling Oxygen and Water Vapor Effects on Optoelectronic Properties of Monolayer Tungsten Disulfide

Zhang, Hanyu; Dunklin, Jeremy R.; Reid, Obadiah G.; Yun, Seok Joon; Nanayakkara, Sanjini U.; Lee, Young Hee; Blackburn, Jeffrey L.; Miller, Elisa M.

doi:10.1039/C9NR09326E

Title: Disentangling Oxygen and Water Vapor Effects on Optoelectronic Properties of Monolayer Tungsten Disulfide

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Abstract

By understanding how the environmental composition impacts the optoelectronic properties of transition metal dichalcogenide monolayers, we demonstrate that simple photoluminescence (PL) measurements of tungsten disulfide (WS₂) monolayers can differentiate relative humidity environments. In this paper, we examine the PL and photoconductivity of chemical vapor deposition grown WS₂ monolayers under three carefully controlled environments: inert gas (N₂), dry air (O₂ in N₂), and humid nitrogen (H₂O vapor in N₂). The WS₂ PL is measured as a function of 532 nm laser power and exposure time and can be decomposed into the exciton, trion, and lower energy state(s) contributions. Under continuous illumination in either O₂ or H₂O vapor environment, we find dramatic (and reversible) increases in PL intensity relative to the PL in an inert environment. The PL bathochromically shifts in an O₂ environment and is dominated by increased trion emission and diminished exciton emission. In contrast, the WS₂ PL increase in a H₂O environment results from an overall increase in emission from all spectral components where the exciton contribution dominates. The drastic increases in PL are anticorrelated with corresponding decreases in photoconductivity, as measured by time-resolved microwave conductivity. The results suggest that both O₂ and H₂O react photochemically with the WS₂more »« less

Authors:

^[1]; Dunklin, Jeremy R. ^[1]; Reid, Obadiah G. ^[1]; Yun, Seok Joon ^[2]; Nanayakkara, Sanjini U. ^[1];

^[2];

^[1];

^[1]

National Renewable Energy Lab. (NREL), Golden, CO (United States)
Inst. for Basic Science (IBS), Suwon (Korea, Republic of)

Publication Date:: 2020-04-01

Research Org.:: National Renewable Energy Lab. (NREL), Golden, CO (United States)

Sponsoring Org.:: USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:: 1659935

Alternate Identifier(s):: OSTI ID: 1607956

Report Number(s):: NREL/JA-5900-73530
Journal ID: ISSN 2040-3372; MainId:6140;UUID:382d332c-974a-e911-9c1c-ac162d87dfe5;MainAdminID:13662

Grant/Contract Number:: AC36-08GO28308

Resource Type:: Accepted Manuscript

Journal Name:: Nanoscale (Online)

Additional Journal Information:: Journal Name: Nanoscale (Online); Journal Volume: 12; Journal Issue: 15; Journal ID: ISSN 2040-3372

Publisher:: Royal Society of Chemistry

Country of Publication:: United States

Language:: English

Subject:: 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; defect states; environmental conditions; monolayer transition-metal dichalcogenides; photoconductivity; photoluminescence; solar-photochemistry

Citation Formats


                    Zhang, Hanyu, Dunklin, Jeremy R., Reid, Obadiah G., Yun, Seok Joon, Nanayakkara, Sanjini U., Lee, Young Hee, Blackburn, Jeffrey L., and Miller, Elisa M.. Disentangling Oxygen and Water Vapor Effects on Optoelectronic Properties of Monolayer Tungsten Disulfide.  United States: N. p., 2020. 
Web.  doi:10.1039/C9NR09326E.

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                    Zhang, Hanyu, Dunklin, Jeremy R., Reid, Obadiah G., Yun, Seok Joon, Nanayakkara, Sanjini U., Lee, Young Hee, Blackburn, Jeffrey L., & Miller, Elisa M.. Disentangling Oxygen and Water Vapor Effects on Optoelectronic Properties of Monolayer Tungsten Disulfide.  United States.  https://doi.org/10.1039/C9NR09326E

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                    Zhang, Hanyu, Dunklin, Jeremy R., Reid, Obadiah G., Yun, Seok Joon, Nanayakkara, Sanjini U., Lee, Young Hee, Blackburn, Jeffrey L., and Miller, Elisa M.. Wed .  
"Disentangling Oxygen and Water Vapor Effects on Optoelectronic Properties of Monolayer Tungsten Disulfide".  United States.  https://doi.org/10.1039/C9NR09326E.  https://www.osti.gov/servlets/purl/1659935.

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@article{osti_1659935,

  title        = {Disentangling Oxygen and Water Vapor Effects on Optoelectronic Properties of Monolayer Tungsten Disulfide},

  author       = {Zhang, Hanyu and Dunklin, Jeremy R. and Reid, Obadiah G. and Yun, Seok Joon and Nanayakkara, Sanjini U. and Lee, Young Hee and Blackburn, Jeffrey L. and Miller, Elisa M.},

  abstractNote = {By understanding how the environmental composition impacts the optoelectronic properties of transition metal dichalcogenide monolayers, we demonstrate that simple photoluminescence (PL) measurements of tungsten disulfide (WS2) monolayers can differentiate relative humidity environments. In this paper, we examine the PL and photoconductivity of chemical vapor deposition grown WS2 monolayers under three carefully controlled environments: inert gas (N2), dry air (O2 in N2), and humid nitrogen (H2O vapor in N2). The WS2 PL is measured as a function of 532 nm laser power and exposure time and can be decomposed into the exciton, trion, and lower energy state(s) contributions. Under continuous illumination in either O2 or H2O vapor environment, we find dramatic (and reversible) increases in PL intensity relative to the PL in an inert environment. The PL bathochromically shifts in an O2 environment and is dominated by increased trion emission and diminished exciton emission. In contrast, the WS2 PL increase in a H2O environment results from an overall increase in emission from all spectral components where the exciton contribution dominates. The drastic increases in PL are anticorrelated with corresponding decreases in photoconductivity, as measured by time-resolved microwave conductivity. The results suggest that both O2 and H2O react photochemically with the WS2 monolayer surface, modifying the optoelectronic properties, but do so via distinct pathways. Thus, we use these optoelectronic differences to differentiate the amount of humidity in the air, which we show with 0%, 40%, and 80% relative humidity environments. This deeper understanding of how ambient conditions impact WS2 monolayers enables novel humidity sensors as well as a better understanding of the correlation between TMDC surface chemistry, light emission, and photoconductivity. Moreover, these WS2 measurements highlight the importance of considering the impact of the local environment on reported results.},

  doi          = {10.1039/C9NR09326E},

  journal      = {Nanoscale (Online)},

  number       = 15,

  volume       = 12,

  place        = {United States},

  year         = {2020},

  month        = {4}

}

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