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Title: Spatially Resolved Photoexcited Charge-Carrier Dynamics in Phase-Engineered Monolayer MoS2

Abstract

A fundamental understanding of the intrinsic optoelectronic properties of atomically thin transition metal dichalcogenides (TMDs) is crucial for its integration into high performance semiconductor devices. We investigate the transport properties of chemical vapor deposition (CVD) grown monolayer molybdenum disulfide (MoS2) under photo-excitation using correlated scanning photocurrent microscopy and photoluminescence imaging. We examined the effect of local phase transformation underneath the metal electrodes on the generation of photocurrent across the channel length with diffraction-limited spatial resolution. While maximum photocurrent generation occurs at the Schottky contacts of semiconducting (2H-phase) MoS2, after the metallic phase transformation (1T-phase), the photocurrent peak is observed towards the center of the device channel, suggesting a strong reduction of native Schottky barriers. Analysis using the bias and position dependence of the photocurrent indicates that the Schottky barrier heights are few meV for 1T- and ~200 meV for 2H-contacted devices. We also demonstrate that a reduction of native Schottky barriers in a 1T device enhances the photo responsivity by more than one order of magnitude, a crucial parameter in achieving high performance optoelectronic devices. The obtained results pave a pathway for the fundamental understanding of intrinsic optoelectronic properties of atomically thin TMDs where Ohmic contacts are necessary for achievingmore » high efficiency devices with low power consumption.« less

Authors:
 [1];  [1];  [2];  [3];  [3];  [4];  [1];  [3];  [3];  [2];  [1];  [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. Rutgers Univ., Piscataway, NJ (United States)
  3. Rice Univ., Houston, TX (United States)
  4. Pacific Light Technologies, Portland, OR (United States)
Publication Date:
Research Org.:
Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1254836
Report Number(s):
LA-UR-14-29662
Journal ID: ISSN 1936-0851
Grant/Contract Number:  
AC52-06NA25396
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
ACS Nano
Additional Journal Information:
Journal Volume: 9; Journal Issue: 1; Journal ID: ISSN 1936-0851
Publisher:
American Chemical Society
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; Material Science

Citation Formats

Yamaguchi, Hisato, Blancon, Jean-Christophe, Kappera, Rajesh, Lei, Sidong, Najmaei, Sina, Mangum, Benjamin D., Gupta, Gautam, Ajayan, Pulickel M., Lou, Jun, Chhowalla, Manish, Crochet, Jared J., and Mohite, Aditya D. Spatially Resolved Photoexcited Charge-Carrier Dynamics in Phase-Engineered Monolayer MoS2. United States: N. p., 2014. Web. doi:10.1021/nn506469v.
Yamaguchi, Hisato, Blancon, Jean-Christophe, Kappera, Rajesh, Lei, Sidong, Najmaei, Sina, Mangum, Benjamin D., Gupta, Gautam, Ajayan, Pulickel M., Lou, Jun, Chhowalla, Manish, Crochet, Jared J., & Mohite, Aditya D. Spatially Resolved Photoexcited Charge-Carrier Dynamics in Phase-Engineered Monolayer MoS2. United States. https://doi.org/10.1021/nn506469v
Yamaguchi, Hisato, Blancon, Jean-Christophe, Kappera, Rajesh, Lei, Sidong, Najmaei, Sina, Mangum, Benjamin D., Gupta, Gautam, Ajayan, Pulickel M., Lou, Jun, Chhowalla, Manish, Crochet, Jared J., and Mohite, Aditya D. 2014. "Spatially Resolved Photoexcited Charge-Carrier Dynamics in Phase-Engineered Monolayer MoS2". United States. https://doi.org/10.1021/nn506469v. https://www.osti.gov/servlets/purl/1254836.
@article{osti_1254836,
title = {Spatially Resolved Photoexcited Charge-Carrier Dynamics in Phase-Engineered Monolayer MoS2},
author = {Yamaguchi, Hisato and Blancon, Jean-Christophe and Kappera, Rajesh and Lei, Sidong and Najmaei, Sina and Mangum, Benjamin D. and Gupta, Gautam and Ajayan, Pulickel M. and Lou, Jun and Chhowalla, Manish and Crochet, Jared J. and Mohite, Aditya D.},
abstractNote = {A fundamental understanding of the intrinsic optoelectronic properties of atomically thin transition metal dichalcogenides (TMDs) is crucial for its integration into high performance semiconductor devices. We investigate the transport properties of chemical vapor deposition (CVD) grown monolayer molybdenum disulfide (MoS2) under photo-excitation using correlated scanning photocurrent microscopy and photoluminescence imaging. We examined the effect of local phase transformation underneath the metal electrodes on the generation of photocurrent across the channel length with diffraction-limited spatial resolution. While maximum photocurrent generation occurs at the Schottky contacts of semiconducting (2H-phase) MoS2, after the metallic phase transformation (1T-phase), the photocurrent peak is observed towards the center of the device channel, suggesting a strong reduction of native Schottky barriers. Analysis using the bias and position dependence of the photocurrent indicates that the Schottky barrier heights are few meV for 1T- and ~200 meV for 2H-contacted devices. We also demonstrate that a reduction of native Schottky barriers in a 1T device enhances the photo responsivity by more than one order of magnitude, a crucial parameter in achieving high performance optoelectronic devices. The obtained results pave a pathway for the fundamental understanding of intrinsic optoelectronic properties of atomically thin TMDs where Ohmic contacts are necessary for achieving high efficiency devices with low power consumption.},
doi = {10.1021/nn506469v},
url = {https://www.osti.gov/biblio/1254836}, journal = {ACS Nano},
issn = {1936-0851},
number = 1,
volume = 9,
place = {United States},
year = {Thu Dec 18 00:00:00 EST 2014},
month = {Thu Dec 18 00:00:00 EST 2014}
}

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Works referenced in this record:

Electric Field Effect in Atomically Thin Carbon Films
journal, October 2004


Controlling the Electronic Structure of Bilayer Graphene
journal, August 2006


A roadmap for graphene
journal, October 2012


Emerging Photoluminescence in Monolayer MoS2
journal, April 2010


Single-layer MoS2 transistors
journal, January 2011


Electronics and optoelectronics of two-dimensional transition metal dichalcogenides
journal, November 2012


The chemistry of two-dimensional layered transition metal dichalcogenide nanosheets
journal, April 2013


Band-like transport in high mobility unencapsulated single-layer MoS 2 transistors
journal, April 2013


Emerging Device Applications for Semiconducting Two-Dimensional Transition Metal Dichalcogenides
journal, January 2014


Evolution of the Electronic Band Structure and Efficient Photo-Detection in Atomic Layers of InSe
journal, January 2014


High Performance Multilayer MoS2Transistors with Scandium Contacts
journal, December 2012


Channel Length Scaling of MoS 2 MOSFETs
journal, September 2012


Intrinsic Electronic Transport Properties of High-Quality Monolayer and Bilayer MoS 2
journal, August 2013


Transport Properties of Monolayer MoS 2 Grown by Chemical Vapor Deposition
journal, March 2014


Photoluminescence from Chemically Exfoliated MoS2
journal, December 2011


Coherent Atomic and Electronic Heterostructures of Single-Layer MoS2
journal, July 2012


Enhanced catalytic activity in strained chemically exfoliated WS2 nanosheets for hydrogen evolution
journal, July 2013


Conducting MoS 2 Nanosheets as Catalysts for Hydrogen Evolution Reaction
journal, November 2013


Phase-engineered low-resistance contacts for ultrathin MoS2 transistors
journal, August 2014


Metallic 1T phase source/drain electrodes for field effect transistors from chemical vapor deposited MoS 2
journal, September 2014


Photoconductivity of Single Carbon Nanotubes
journal, August 2003


Scanning Photocurrent Imaging and Electronic Band Studies in Silicon Nanowire Field Effect Transistors
journal, July 2005


Quantitative Measurement of the Electron and Hole Mobility−Lifetime Products in Semiconductor Nanowires
journal, April 2006


Field-Enhanced Photocurrent Spectroscopy of Excitonic States in Single-Wall Carbon Nanotubes
journal, July 2006


Photocurrent Imaging of p−n Junctions in Ambipolar Carbon Nanotube Transistors
journal, October 2007


Imaging of the Schottky Barriers and Charge Depletion in Carbon Nanotube Transistors
journal, July 2007


Electronic-Band-Structure Mapping of Nanotube Transistors by Scanning Photocurrent Microscopy
journal, December 2007


Role of contacts in graphene transistors: A scanning photocurrent study
journal, June 2009


Observation of the triplet exciton in EuS-coated single-walled nanotubes
journal, June 2009


Ultrafast hot-carrier-dominated photocurrent in graphene
journal, January 2012


Controlled Ambipolar Doping and Gate Voltage Dependent Carrier Diffusion Length in Lead Sulfide Nanowires
journal, October 2012


Gate-tunable carbon nanotube-MoS2 heterojunction p-n diode
journal, October 2013


Photothermoelectric Effect in Suspended Semiconducting Carbon Nanotubes
journal, December 2013


Scanning Photocurrent Microscopy in Semiconductor Nanostructures
journal, September 2013


Elucidating the Photoresponse of Ultrathin MoS 2 Field-Effect Transistors by Scanning Photocurrent Microscopy
journal, July 2013


Vapour phase growth and grain boundary structure of molybdenum disulphide atomic layers
journal, June 2013


Tailoring the Physical Properties of Molybdenum Disulfide Monolayers by Control of Interfacial Chemistry
journal, February 2014


Charge carrier mobility and lifetime of organic bulk heterojunctions analyzed by impedance spectroscopy
journal, October 2008


Bimolecular recombination in polymer/fullerene bulk heterojunction solar cells
journal, January 2006


Quantifying Bimolecular Recombination in Organic Solar Cells in Steady State
journal, May 2013


Electrothermal Dynamics of Semiconductor Nanowires under Local Carrier Modulation
journal, September 2011


Large and Tunable Photothermoelectric Effect in Single-Layer MoS 2
journal, January 2013


Photoconductivity of biased graphene
journal, December 2012


Mechanisms of Photoconductivity in Atomically Thin MoS 2
journal, October 2014


Single-Layer MoS2 Phototransistors
journal, December 2011


High-Detectivity Multilayer MoS 2 Phototransistors with Spectral Response from Ultraviolet to Infrared
journal, August 2012


Transferring and Identification of Single- and Few-Layer Graphene on Arbitrary Substrates
journal, October 2008


Works referencing / citing this record:

Layer-dependent ultrafast dynamics of α -In 2 Se 3 nanoflakes
journal, May 2019


Atomic-layer soft plasma etching of MoS2
journal, January 2016


Recent progress of TMD nanomaterials: phase transitions and applications
journal, January 2020


Ultrasensitive MoS2 photodetector by serial nano-bridge multi-heterojunction
journal, October 2019


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


Contact morphology and revisited photocurrent dynamics in monolayer MoS2
journal, November 2017


A Versatile Scanning Photocurrent Mapping System to Characterize Optoelectronic Devices based on 2D Materials
journal, May 2017


Phase-selective synthesis of 1T′ MoS2 monolayers and heterophase bilayers
journal, October 2018


Photonic crystallization of two-dimensional MoS 2 for stretchable photodetectors
journal, January 2019


Diversity of structural and electronic properties of P –AuBr of different dimensions
journal, March 2019


Synthesis, stabilization and applications of 2-dimensional 1T metallic MoS 2
journal, January 2018


Interactions between lasers and two-dimensional transition metal dichalcogenides
journal, January 2016


Contact morphology and revisited photocurrent dynamics in monolayer MoS2
preprint, January 2017


Atomic-layer soft plasma etching of MoS2
journal, January 2016


Nanoscale imaging of the photoresponse in PN junctions of InGaAs infrared detector
journal, February 2016