Observation of Ultrafast Free Carrier Dynamics in Single Layer MoS2

Antonija Grubisic Cabo; Jill A. Miwa; Signe Grønborg Sørensen; Jonathon M. Riley; Jens C. Johannsen; Cephise Cacho; Oliver Alexander; Richard T. Chapman; Emma Springate; Marco Grioni; Jeppe V. Lauritsen; Phil D. C. King; Philip Hofmann; Søren Ulstrup

doi:10.1021/acs.nanolett.5b01967

Observation of Ultrafast Free Carrier Dynamics in Single Layer MoS₂

Antonija Grubisic Cabo, Jill A. Miwa, Signe Grønborg Sørensen, Jonathon M. Riley, Jens C. Johannsen, Cephise Cacho, Oliver Alexander, Richard T. Chapman, Emma Springate, Marco Grioni, Jeppe V. Lauritsen, Phil D. C. King, Philip Hofmann^*, Søren Ulstrup

^*Corresponding author for this work

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaper › Journal article › Research › peer-review

152 Citations (Scopus)

Abstract

The dynamics of excited electrons and holes in single layer (SL) MoS2 have so far been difficult to disentangle from the excitons that dominate the optical response of this material. Here, we use time- and angle-resolved photoemission spectroscopy for a SL of MoS2 on a metallic substrate to directly measure the excited free carriers. This allows us to ascertain a direct quasipartide band gap of 1.95 eV and determine an ultrafast (50 fs) extraction of excited free carriers via the metal in contact with the SL MoS2. This process is of key importance for optoelectronic applications that rely on separated free carriers rather than excitons.

Original language	English
Journal	Nano Letters
Volume	15
Issue	9
Pages (from-to)	5883-5887
Number of pages	5
ISSN	1530-6984
DOIs	https://doi.org/10.1021/acs.nanolett.5b01967
Publication status	Published - 2015

Keywords

Transition metal dichalcogenides
MoS2
free carriers
excitons
time- and angle-resolved photoemission spectroscopy
VALLEY POLARIZATION
MONOLAYER MOS2
QUANTUM-WELLS
EXCITONS
HETEROSTRUCTURES
RECOMBINATION
TRANSITION
HELICITY
BANDGAP
GAAS

Access to Document

10.1021/acs.nanolett.5b01967

Cite this

@article{9dcef49303d149c1a020f39c977c9e57,

title = "Observation of Ultrafast Free Carrier Dynamics in Single Layer MoS2",

abstract = "The dynamics of excited electrons and holes in single layer (SL) MoS2 have so far been difficult to disentangle from the excitons that dominate the optical response of this material. Here, we use time- and angle-resolved photoemission spectroscopy for a SL of MoS2 on a metallic substrate to directly measure the excited free carriers. This allows us to ascertain a direct quasipartide band gap of 1.95 eV and determine an ultrafast (50 fs) extraction of excited free carriers via the metal in contact with the SL MoS2. This process is of key importance for optoelectronic applications that rely on separated free carriers rather than excitons.",

keywords = "Transition metal dichalcogenides, MoS2, free carriers, excitons, time- and angle-resolved photoemission spectroscopy, VALLEY POLARIZATION, MONOLAYER MOS2, QUANTUM-WELLS, EXCITONS, HETEROSTRUCTURES, RECOMBINATION, TRANSITION, HELICITY, BANDGAP, GAAS",

author = "Cabo, {Antonija Grubisic} and Miwa, {Jill A.} and S{\o}rensen, {Signe Gr{\o}nborg} and Riley, {Jonathon M.} and Johannsen, {Jens C.} and Cephise Cacho and Oliver Alexander and Chapman, {Richard T.} and Emma Springate and Marco Grioni and Lauritsen, {Jeppe V.} and King, {Phil D. C.} and Philip Hofmann and S{\o}ren Ulstrup",

year = "2015",

doi = "10.1021/acs.nanolett.5b01967",

language = "English",

volume = "15",

pages = "5883--5887",

journal = "Nano Letters",

issn = "1530-6984",

publisher = "American Chemical Society",

number = "9",

}

TY - JOUR

T1 - Observation of Ultrafast Free Carrier Dynamics in Single Layer MoS2

AU - Cabo, Antonija Grubisic

AU - Miwa, Jill A.

AU - Sørensen, Signe Grønborg

AU - Riley, Jonathon M.

AU - Johannsen, Jens C.

AU - Cacho, Cephise

AU - Alexander, Oliver

AU - Chapman, Richard T.

AU - Springate, Emma

AU - Grioni, Marco

AU - Lauritsen, Jeppe V.

AU - King, Phil D. C.

AU - Hofmann, Philip

AU - Ulstrup, Søren

PY - 2015

Y1 - 2015

N2 - The dynamics of excited electrons and holes in single layer (SL) MoS2 have so far been difficult to disentangle from the excitons that dominate the optical response of this material. Here, we use time- and angle-resolved photoemission spectroscopy for a SL of MoS2 on a metallic substrate to directly measure the excited free carriers. This allows us to ascertain a direct quasipartide band gap of 1.95 eV and determine an ultrafast (50 fs) extraction of excited free carriers via the metal in contact with the SL MoS2. This process is of key importance for optoelectronic applications that rely on separated free carriers rather than excitons.

AB - The dynamics of excited electrons and holes in single layer (SL) MoS2 have so far been difficult to disentangle from the excitons that dominate the optical response of this material. Here, we use time- and angle-resolved photoemission spectroscopy for a SL of MoS2 on a metallic substrate to directly measure the excited free carriers. This allows us to ascertain a direct quasipartide band gap of 1.95 eV and determine an ultrafast (50 fs) extraction of excited free carriers via the metal in contact with the SL MoS2. This process is of key importance for optoelectronic applications that rely on separated free carriers rather than excitons.

KW - Transition metal dichalcogenides

KW - MoS2

KW - free carriers

KW - excitons

KW - time- and angle-resolved photoemission spectroscopy

KW - VALLEY POLARIZATION

KW - MONOLAYER MOS2

KW - QUANTUM-WELLS

KW - EXCITONS

KW - HETEROSTRUCTURES

KW - RECOMBINATION

KW - TRANSITION

KW - HELICITY

KW - BANDGAP

KW - GAAS

U2 - 10.1021/acs.nanolett.5b01967

DO - 10.1021/acs.nanolett.5b01967

M3 - Journal article

C2 - 26315566

SN - 1530-6984

VL - 15

SP - 5883

EP - 5887

JO - Nano Letters

JF - Nano Letters

IS - 9