DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Measuring Photoexcited Free Charge Carriers in Mono- to Few-Layer Transition-Metal Dichalcogenides with Steady-State Microwave Conductivity

Abstract

We present that photoinduced generation of mobile charge carriers is the fundamental process underlying many applications, such as solar energy harvesting, solar fuel production, and efficient photodetectors. Monolayer transition-metal dichalcogenides (TMDCs) are an attractive model system for studying photoinduced carrier generation mechanisms in low-dimensional materials because they possess strong direct band gap absorption, large exciton binding energies, and are only a few atoms thick. While a number of studies have observed charge generation in neat TMDCs for photoexcitation at, above, or even below the optical band gap, the role of nonlinear processes (resulting from high photon fluences), defect states, excess charges, and layer interactions remains unclear. In this study, we introduce steady-state microwave conductivity (SSMC) spectroscopy for measuring charge generation action spectra in a model WS2 mono- to few-layer TMDC system at fluences that coincide with the terrestrial solar flux. Despite utilizing photon fluences well below those used in previous pump-probe measurements, the SSMC technique is sensitive enough to easily resolve the photoconductivity spectrum arising in mono- to few-layer WS2. By correlating SSMC with other spectroscopy and microscopy experiments, we find that photoconductivity is observed predominantly for excitation wavelengths resonant with the excitonic transition of the multilayer portions of themore » sample, the density of which can be controlled by the synthesis conditions. Lastly, these results highlight the potential of layer engineering as a route toward achieving high yields of photoinduced charge carriers in neat TMDCs, with implications for a broad range of optoelectronic applications.« less

Authors:
ORCiD logo [1]; ORCiD logo [1];  [2]; ORCiD logo [1];  [3];  [4];  [1]; ORCiD logo [5];  [6]; ORCiD logo [6]; ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [2]
  1. National Renewable Energy Lab. (NREL), Golden, CO (United States)
  2. National Renewable Energy Lab. (NREL), Golden, CO (United States); Univ. of Colorado, Boulder, CO (United States)
  3. Warren Wilson College, Swannanoa, NC (United States)
  4. Univ. of Colorado, Boulder, CO (United States)
  5. Institute for Basic Science (IBS), Suwon (Korea)
  6. Institute for Basic Science (IBS), Suwon (Korea); Sungkyunkwan Univ., Suwon (Korea)
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences, and Biosciences Division
OSTI Identifier:
1580328
Report Number(s):
NREL/JA-5K00-75256
Journal ID: ISSN 1948-7185; TRN: US2102245
Grant/Contract Number:  
AC36-08GO28308
Resource Type:
Accepted Manuscript
Journal Name:
Journal of Physical Chemistry Letters
Additional Journal Information:
Journal Volume: 11; Journal Issue: 1; Journal ID: ISSN 1948-7185
Publisher:
American Chemical Society
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; charge generation; transition-metal dichalcogenides; photoconductivity

Citation Formats

Blackburn, Jeffrey L., Zhang, Hanyu, Myers, Alexis R., Dunklin, Jeremy R., Coffey, David C., Hirsch, Rebecca N., Vigil-Fowler, Derek W., Yun, Seok Joon, Cho, Byeong Wook, Lee, Young Hee, Miller, Elisa M., Rumbles, Garry, and Reid, Obadiah G. Measuring Photoexcited Free Charge Carriers in Mono- to Few-Layer Transition-Metal Dichalcogenides with Steady-State Microwave Conductivity. United States: N. p., 2019. Web. doi:10.1021/acs.jpclett.9b03117.
Blackburn, Jeffrey L., Zhang, Hanyu, Myers, Alexis R., Dunklin, Jeremy R., Coffey, David C., Hirsch, Rebecca N., Vigil-Fowler, Derek W., Yun, Seok Joon, Cho, Byeong Wook, Lee, Young Hee, Miller, Elisa M., Rumbles, Garry, & Reid, Obadiah G. Measuring Photoexcited Free Charge Carriers in Mono- to Few-Layer Transition-Metal Dichalcogenides with Steady-State Microwave Conductivity. United States. https://doi.org/10.1021/acs.jpclett.9b03117
Blackburn, Jeffrey L., Zhang, Hanyu, Myers, Alexis R., Dunklin, Jeremy R., Coffey, David C., Hirsch, Rebecca N., Vigil-Fowler, Derek W., Yun, Seok Joon, Cho, Byeong Wook, Lee, Young Hee, Miller, Elisa M., Rumbles, Garry, and Reid, Obadiah G. Mon . "Measuring Photoexcited Free Charge Carriers in Mono- to Few-Layer Transition-Metal Dichalcogenides with Steady-State Microwave Conductivity". United States. https://doi.org/10.1021/acs.jpclett.9b03117. https://www.osti.gov/servlets/purl/1580328.
@article{osti_1580328,
title = {Measuring Photoexcited Free Charge Carriers in Mono- to Few-Layer Transition-Metal Dichalcogenides with Steady-State Microwave Conductivity},
author = {Blackburn, Jeffrey L. and Zhang, Hanyu and Myers, Alexis R. and Dunklin, Jeremy R. and Coffey, David C. and Hirsch, Rebecca N. and Vigil-Fowler, Derek W. and Yun, Seok Joon and Cho, Byeong Wook and Lee, Young Hee and Miller, Elisa M. and Rumbles, Garry and Reid, Obadiah G.},
abstractNote = {We present that photoinduced generation of mobile charge carriers is the fundamental process underlying many applications, such as solar energy harvesting, solar fuel production, and efficient photodetectors. Monolayer transition-metal dichalcogenides (TMDCs) are an attractive model system for studying photoinduced carrier generation mechanisms in low-dimensional materials because they possess strong direct band gap absorption, large exciton binding energies, and are only a few atoms thick. While a number of studies have observed charge generation in neat TMDCs for photoexcitation at, above, or even below the optical band gap, the role of nonlinear processes (resulting from high photon fluences), defect states, excess charges, and layer interactions remains unclear. In this study, we introduce steady-state microwave conductivity (SSMC) spectroscopy for measuring charge generation action spectra in a model WS2 mono- to few-layer TMDC system at fluences that coincide with the terrestrial solar flux. Despite utilizing photon fluences well below those used in previous pump-probe measurements, the SSMC technique is sensitive enough to easily resolve the photoconductivity spectrum arising in mono- to few-layer WS2. By correlating SSMC with other spectroscopy and microscopy experiments, we find that photoconductivity is observed predominantly for excitation wavelengths resonant with the excitonic transition of the multilayer portions of the sample, the density of which can be controlled by the synthesis conditions. Lastly, these results highlight the potential of layer engineering as a route toward achieving high yields of photoinduced charge carriers in neat TMDCs, with implications for a broad range of optoelectronic applications.},
doi = {10.1021/acs.jpclett.9b03117},
journal = {Journal of Physical Chemistry Letters},
number = 1,
volume = 11,
place = {United States},
year = {Mon Dec 02 00:00:00 EST 2019},
month = {Mon Dec 02 00:00:00 EST 2019}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Citation Metrics:
Cited by: 8 works
Citation information provided by
Web of Science

Save / Share:

Works referenced in this record:

Progress, Challenges, and Opportunities in Two-Dimensional Materials Beyond Graphene
journal, March 2013

  • Butler, Sheneve Z.; Hollen, Shawna M.; Cao, Linyou
  • ACS Nano, Vol. 7, Issue 4, p. 2898-2926
  • DOI: 10.1021/nn400280c

Two-Dimensional Transition Metal Dichalcogenides under Electron Irradiation: Defect Production and Doping
journal, July 2012


Synthesis, Properties, and Applications of Transition Metal-Doped Layered Transition Metal Dichalcogenides
journal, March 2016


Tunable Band Gap Photoluminescence from Atomically Thin Transition-Metal Dichalcogenide Alloys
journal, April 2013

  • Chen, Yanfeng; Xi, Jinyang; Dumcenco, Dumitru O.
  • ACS Nano, Vol. 7, Issue 5, p. 4610-4616
  • DOI: 10.1021/nn401420h

Atomically Thin MoS2 A New Direct-Gap Semiconductor
journal, September 2010


Dimensional Reduction of a Layered Metal Chalcogenide into a 1D Near-IR Direct Band Gap Semiconductor
journal, March 2012

  • Liu, Yi-Hsin; Porter, Spencer H.; Goldberger, Joshua E.
  • Journal of the American Chemical Society, Vol. 134, Issue 11
  • DOI: 10.1021/ja211765y

Ultrafast Exciton Dissociation and Long-Lived Charge Separation in a Photovoltaic Pentacene–MoS 2 van der Waals Heterojunction
journal, December 2016


Mechanisms of Ultrafast Charge Separation in a PTB7/Monolayer MoS 2 van der Waals Heterojunction
journal, April 2018

  • Zhong, Chengmei; Sangwan, Vinod K.; Wang, Chen
  • The Journal of Physical Chemistry Letters, Vol. 9, Issue 10
  • DOI: 10.1021/acs.jpclett.8b00628

Photocarrier generation from interlayer charge-transfer transitions in WS 2 -graphene heterostructures
journal, February 2018


High-Performance Transition Metal Dichalcogenide Photodetectors Enhanced by Self-Assembled Monolayer Doping
journal, May 2015

  • Kang, Dong-Ho; Kim, Myung-Soo; Shim, Jaewoo
  • Advanced Functional Materials, Vol. 25, Issue 27
  • DOI: 10.1002/adfm.201501170

Ultrafast response of monolayer molybdenum disulfide photodetectors
journal, November 2015

  • Wang, Haining; Zhang, Changjian; Chan, Weimin
  • Nature Communications, Vol. 6, Issue 1
  • DOI: 10.1038/ncomms9831

Single-Layer MoS2 Phototransistors
journal, December 2011

  • Yin, Zongyou; Li, Hai; Li, Hong
  • ACS Nano, Vol. 6, Issue 1, p. 74-80
  • DOI: 10.1021/nn2024557

Electronic Band Structures of Molybdenum and Tungsten Dichalcogenides by the GW Approach
journal, March 2012

  • Jiang, Hong
  • The Journal of Physical Chemistry C, Vol. 116, Issue 14
  • DOI: 10.1021/jp300079d

Identification of Active Edge Sites for Electrochemical H2 Evolution from MoS2 Nanocatalysts
journal, July 2007

  • Jaramillo, T. F.; Jorgensen, K. P.; Bonde, J.
  • Science, Vol. 317, Issue 5834, p. 100-102
  • DOI: 10.1126/science.1141483

Balancing the Hydrogen Evolution Reaction, Surface Energetics, and Stability of Metallic MoS 2 Nanosheets via Covalent Functionalization
journal, December 2017

  • Benson, Eric E.; Zhang, Hanyu; Schuman, Samuel A.
  • Journal of the American Chemical Society, Vol. 140, Issue 1
  • DOI: 10.1021/jacs.7b11242

Nanoscale mapping of hydrogen evolution on metallic and semiconducting MoS 2 nanosheets
journal, January 2019

  • Sun, Tong; Zhang, Hanyu; Wang, Xiang
  • Nanoscale Horizons, Vol. 4, Issue 3
  • DOI: 10.1039/C8NH00346G

Molybdenum sulfides—efficient and viable materials for electro - and photoelectrocatalytic hydrogen evolution
journal, January 2012

  • Laursen, Anders B.; Kegnæs, Søren; Dahl, Søren
  • Energy & Environmental Science, Vol. 5, Issue 2
  • DOI: 10.1039/c2ee02618j

Exciton Binding Energy of Monolayer WS2
journal, March 2015

  • Zhu, Bairen; Chen, Xi; Cui, Xiaodong
  • Scientific Reports, Vol. 5, Issue 1
  • DOI: 10.1038/srep09218

Theory of neutral and charged excitons in monolayer transition metal dichalcogenides
journal, July 2013

  • Berkelbach, Timothy C.; Hybertsen, Mark S.; Reichman, David R.
  • Physical Review B, Vol. 88, Issue 4
  • DOI: 10.1103/PhysRevB.88.045318

Giant bandgap renormalization and excitonic effects in a monolayer transition metal dichalcogenide semiconductor
journal, August 2014

  • Ugeda, Miguel M.; Bradley, Aaron J.; Shi, Su-Fei
  • Nature Materials, Vol. 13, Issue 12
  • DOI: 10.1038/nmat4061

Tightly bound trions in monolayer MoS2
journal, December 2012

  • Mak, Kin Fai; He, Keliang; Lee, Changgu
  • Nature Materials, Vol. 12, Issue 3
  • DOI: 10.1038/nmat3505

Long-Lived Charge Separation at Heterojunctions between Semiconducting Single-Walled Carbon Nanotubes and Perylene Diimide Electron Acceptors
journal, December 2017

  • Kang, Hyun Suk; Sisto, Thomas J.; Peurifoy, Samuel
  • The Journal of Physical Chemistry C, Vol. 122, Issue 25
  • DOI: 10.1021/acs.jpcc.8b01400

Ultrafast Spectroscopic Signature of Charge Transfer between Single-Walled Carbon Nanotubes and C 60
journal, July 2014

  • Dowgiallo, Anne-Marie; Mistry, Kevin S.; Johnson, Justin C.
  • ACS Nano, Vol. 8, Issue 8
  • DOI: 10.1021/nn503271k

Free Carrier Generation and Recombination in Polymer-Wrapped Semiconducting Carbon Nanotube Films and Heterojunctions
journal, October 2013

  • Bindl, Dominick J.; Ferguson, Andrew J.; Wu, Meng-Yin
  • The Journal of Physical Chemistry Letters, Vol. 4, Issue 21
  • DOI: 10.1021/jz401711m

Ultrafast Charge Separation and Indirect Exciton Formation in a MoS 2 –MoSe 2 van der Waals Heterostructure
journal, November 2014

  • Ceballos, Frank; Bellus, Matthew Z.; Chiu, Hsin-Ying
  • ACS Nano, Vol. 8, Issue 12
  • DOI: 10.1021/nn505736z

Ultrafast dynamics in van der Waals heterostructures
journal, November 2018


Ultrafast charge transfer in atomically thin MoS2/WS2 heterostructures
journal, August 2014

  • Hong, Xiaoping; Kim, Jonghwan; Shi, Su-Fei
  • Nature Nanotechnology, Vol. 9, Issue 9
  • DOI: 10.1038/nnano.2014.167

Highly mobile charge-transfer excitons in two-dimensional WS 2 /tetracene heterostructures
journal, January 2018


Photoinduced spontaneous free-carrier generation in semiconducting single-walled carbon nanotubes
journal, November 2015

  • Park, Jaehong; Reid, Obadiah G.; Blackburn, Jeffrey L.
  • Nature Communications, Vol. 6, Issue 1
  • DOI: 10.1038/ncomms9809

Charge Trapping and Exciton Dynamics in Large-Area CVD Grown MoS 2
journal, January 2016

  • Cunningham, Paul D.; McCreary, Kathleen M.; Hanbicki, Aubrey T.
  • The Journal of Physical Chemistry C, Vol. 120, Issue 10
  • DOI: 10.1021/acs.jpcc.6b00647

Ultrafast Transient Terahertz Conductivity of Monolayer MoS 2 and WSe 2 Grown by Chemical Vapor Deposition
journal, November 2014

  • Docherty, Callum J.; Parkinson, Patrick; Joyce, Hannah J.
  • ACS Nano, Vol. 8, Issue 11
  • DOI: 10.1021/nn5034746

Two-dimensional transition metal dichalcogenides: interface and defect engineering
journal, January 2018

  • Hu, Zehua; Wu, Zhangting; Han, Cheng
  • Chemical Society Reviews, Vol. 47, Issue 9
  • DOI: 10.1039/C8CS00024G

Direct Observation of Degenerate Two-Photon Absorption and Its Saturation in WS 2 and MoS 2 Monolayer and Few-Layer Films
journal, June 2015


Giant two-photon absorption in monolayer MoS 2 : Giant two-photon absorption in monolayer MoS
journal, June 2015

  • Li, Yuanxin; Dong, Ningning; Zhang, Saifeng
  • Laser & Photonics Reviews, Vol. 9, Issue 4
  • DOI: 10.1002/lpor.201500052

Exciton fission in monolayer transition metal dichalcogenide semiconductors
journal, October 2017


Photoinduced Bandgap Renormalization and Exciton Binding Energy Reduction in WS 2
journal, October 2016

  • Cunningham, Paul D.; Hanbicki, Aubrey T.; McCreary, Kathleen M.
  • ACS Nano, Vol. 11, Issue 12
  • DOI: 10.1021/acsnano.7b06885

Exciton Dynamics, Transport, and Annihilation in Atomically Thin Two-Dimensional Semiconductors
journal, July 2017


Steady-state microwave conductivity reveals mobility-lifetime product in methylammonium lead iodide
journal, October 2018

  • Labram, John G.; Perry, Erin E.; Venkatesan, Naveen R.
  • Applied Physics Letters, Vol. 113, Issue 15
  • DOI: 10.1063/1.5041959

Trap-limited carrier recombination in single-walled carbon nanotube heterojunctions with fullerene acceptor layers
journal, June 2015

  • Ferguson, Andrew J.; Dowgiallo, Anne-Marie; Bindl, Dominick J.
  • Physical Review B, Vol. 91, Issue 24
  • DOI: 10.1103/PhysRevB.91.245311

Tuning the driving force for exciton dissociation in single-walled carbon nanotube heterojunctions
journal, April 2016

  • Ihly, Rachelle; Mistry, Kevin S.; Ferguson, Andrew J.
  • Nature Chemistry, Vol. 8, Issue 6
  • DOI: 10.1038/nchem.2496

Quantitative analysis of time-resolved microwave conductivity data
journal, November 2017

  • Reid, Obadiah G.; Moore, David T.; Li, Zhen
  • Journal of Physics D: Applied Physics, Vol. 50, Issue 49
  • DOI: 10.1088/1361-6463/aa9559

Grain-Size-Limited Mobility in Methylammonium Lead Iodide Perovskite Thin Films
journal, August 2016


Identification of individual and few layers of WS2 using Raman Spectroscopy
journal, April 2013

  • Berkdemir, Ayse; Gutiérrez, Humberto R.; Botello-Méndez, Andrés R.
  • Scientific Reports, Vol. 3, Issue 1
  • DOI: 10.1038/srep01755

Extraordinary Room-Temperature Photoluminescence in Triangular WS 2 Monolayers
journal, December 2012

  • Gutiérrez, Humberto R.; Perea-López, Nestor; Elías, Ana Laura
  • Nano Letters, Vol. 13, Issue 8
  • DOI: 10.1021/nl3026357

Engineering Optical and Electronic Properties of WS 2 by Varying the Number of Layers
journal, June 2015


Thickness-Dependent Differential Reflectance Spectra of Monolayer and Few-Layer MoS2, MoSe2, WS2 and WSe2
journal, September 2018

  • Niu, Yue; Gonzalez-Abad, Sergio; Frisenda, Riccardo
  • Nanomaterials, Vol. 8, Issue 9
  • DOI: 10.3390/nano8090725

Evolution of Electronic Structure in Atomically Thin Sheets of WS 2 and WSe 2
journal, December 2012

  • Zhao, Weijie; Ghorannevis, Zohreh; Chu, Leiqiang
  • ACS Nano, Vol. 7, Issue 1
  • DOI: 10.1021/nn305275h

Ultrafast time-resolved investigations of excitons and biexcitons at room temperature in layered WS 2
journal, November 2018

  • Chowdhury, Rup K.; Nandy, Snehasish; Bhattacharya, Sayantan
  • 2D Materials, Vol. 6, Issue 1
  • DOI: 10.1088/2053-1583/aae872

Exciton and charge carrier dynamics in few-layer WS 2
journal, January 2016

  • Vega-Mayoral, Victor; Vella, Daniele; Borzda, Tetiana
  • Nanoscale, Vol. 8, Issue 10
  • DOI: 10.1039/C5NR08384B

The optical response of monolayer, few-layer and bulk tungsten disulfide
journal, January 2017

  • Molas, Maciej R.; Nogajewski, Karol; Slobodeniuk, Artur O.
  • Nanoscale, Vol. 9, Issue 35
  • DOI: 10.1039/C7NR04672C

Efficiency of Charge-Transfer Doping in Organic Semiconductors Probed with Quantitative Microwave and Direct-Current Conductance
journal, November 2018

  • Ferguson, Andrew J.; Reid, Obadiah G.; Nanayakkara, Sanjini U.
  • The Journal of Physical Chemistry Letters, Vol. 9, Issue 23
  • DOI: 10.1021/acs.jpclett.8b03074

Large n- and p-type thermoelectric power factors from doped semiconducting single-walled carbon nanotube thin films
journal, January 2017

  • MacLeod, Bradley A.; Stanton, Noah J.; Gould, Isaac E.
  • Energy & Environmental Science, Vol. 10, Issue 10
  • DOI: 10.1039/C7EE01130J

Tailored semiconducting carbon nanotube networks with enhanced thermoelectric properties
journal, April 2016


Effects of confinement and environment on the electronic structure and exciton binding energy of MoS 2 from first principles
journal, December 2012


Quasiparticle band structure calculation of monolayer, bilayer, and bulk MoS 2
journal, May 2012


Observation of Excitonic Rydberg States in Monolayer MoS 2 and WS 2 by Photoluminescence Excitation Spectroscopy
journal, April 2015

  • Hill, Heather M.; Rigosi, Albert F.; Roquelet, Cyrielle
  • Nano Letters, Vol. 15, Issue 5
  • DOI: 10.1021/nl504868p

Exciton Binding Energy and Nonhydrogenic Rydberg Series in Monolayer WS 2
journal, August 2014


Exciton Radiative Lifetimes in Two-Dimensional Transition Metal Dichalcogenides
journal, March 2015

  • Palummo, Maurizia; Bernardi, Marco; Grossman, Jeffrey C.
  • Nano Letters, Vol. 15, Issue 5
  • DOI: 10.1021/nl503799t

Optical identification of sulfur vacancies: Bound excitons at the edges of monolayer tungsten disulfide
journal, April 2017

  • Carozo, Victor; Wang, Yuanxi; Fujisawa, Kazunori
  • Science Advances, Vol. 3, Issue 4
  • DOI: 10.1126/sciadv.1602813

Origin of n -type conductivity of monolayer MoS 2
journal, March 2019


Visualizing band offsets and edge states in bilayer–monolayer transition metal dichalcogenides lateral heterojunction
journal, January 2016

  • Zhang, Chendong; Chen, Yuxuan; Huang, Jing-Kai
  • Nature Communications, Vol. 7, Issue 1
  • DOI: 10.1038/ncomms10349

Investigation of Band-Offsets at Monolayer–Multilayer MoS 2 Junctions by Scanning Photocurrent Microscopy
journal, March 2015

  • Howell, Sarah L.; Jariwala, Deep; Wu, Chung-Chiang
  • Nano Letters, Vol. 15, Issue 4
  • DOI: 10.1021/nl504311p

Can we use time-resolved measurements to get steady-state transport data for halide perovskites?
journal, September 2018

  • Levine, Igal; Gupta, Satyajit; Bera, Achintya
  • Journal of Applied Physics, Vol. 124, Issue 10
  • DOI: 10.1063/1.5037637

Revealing the Dynamics of Charge Carriers in Polymer:Fullerene Blends Using Photoinduced Time-Resolved Microwave Conductivity
journal, October 2013

  • Savenije, Tom J.; Ferguson, Andrew J.; Kopidakis, Nikos
  • The Journal of Physical Chemistry C, Vol. 117, Issue 46
  • DOI: 10.1021/jp406706u