Spectroscopic correlation of chalcogen defects in atomically thin MoS2(1−x)Se2x alloys

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Spectroscopic correlation of chalcogen defects in atomically thin MoS2(1−x)Se2x alloys. / Sharma, Rahul; Pandey, Juhi; Sahoo, Krishna Rani; Rana, Kewal Singh; Biroju, Ravi K.; Theis, Wolfgang; Soni, Ajay; Narayanan, Tharangattu N.

In: JPhys Materials, Vol. 3, No. 4, 045001, 20.08.2020.

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Sharma, Rahul ; Pandey, Juhi ; Sahoo, Krishna Rani ; Rana, Kewal Singh ; Biroju, Ravi K. ; Theis, Wolfgang ; Soni, Ajay ; Narayanan, Tharangattu N. / Spectroscopic correlation of chalcogen defects in atomically thin MoS2(1−x)Se2x alloys. In: JPhys Materials. 2020 ; Vol. 3, No. 4.

Bibtex

@article{2bca44474d054d359932d9c8cbcb2ebb,
title = "Spectroscopic correlation of chalcogen defects in atomically thin MoS2(1−x)Se2x alloys",
abstract = "Engineering of atomically thin transition metal dichalcogenides (TMDs) is highly sought after for novel optoelectronic and spintronic devices. With the limited number of naturally existing TMDs, chalcogen based alloying has become a viable solution for developing TMDs for optical modulators and photovoltaics. Here, we report on detailed optical and microscopic studies of ternary TMD alloys of molybdenum, sulfur, and selenium grown via a single step method. The developed material has tunable band gaps in a broad range 1.5–1.9 eV with the variation in sulfur compositions. Further, the existence of trions, bi-excitons, and defect bound excitons are shown using temperature dependent (4 K−300 K) photoluminescence spectroscopy. A detailed analysis on MoS1.34Se0.66 alloy system shows the evidence of new types of defect bound excitons originating at low temperatures along with the presence of bi-excitons having a binding energy of ∼41 meV. The prospects of defect induced quasiparticles are observed in scanning transmission electron microscope assisted analyses and verified using density functional theory calculations. The thermal conductivity values, calculated using micro-Raman studies, of MoS2, MoSe2, and MoS1.34Se0.66 are found to be 69(±2) W m−1 K−1, 33(±2) W m−1 K−1 and 17(±2) W m−1 K−1 respectively, in agreement with the theoretical predictions. Tunable optical properties of these ternary atomic layers along with moderate thermal conductivity reveal the potential of these layers in modern opto-electronic devices and sensors.",
keywords = "2D materials, Bi-excitons, Defect bound excitons, Density functional theory, Photoluminescence, Thermal conductivity, TMDs",
author = "Rahul Sharma and Juhi Pandey and Sahoo, {Krishna Rani} and Rana, {Kewal Singh} and Biroju, {Ravi K.} and Wolfgang Theis and Ajay Soni and Narayanan, {Tharangattu N.}",
note = "Funding Information: Authors thank support from the intramural grants at TIFR Hyderabad from the Department of Atomic Energy (DAE). RS thanks Sumit Bawari for helpful discussion about DFT calculations. Ravi K. Biroju and Wolfgang Theis acknowledge the Marie-Sklodowska-Curie individual fellowship under EU H2020 Programme (H2020-MSCA-IF-2017; Grant No: 750929) to carry out some part of this work. AS acknowledges IIT Mandi for low temperature Raman PL facilities. Publisher Copyright: {\textcopyright} 2020 The Author(s). Published by IOP Publishing Ltd",
year = "2020",
month = aug,
day = "20",
doi = "10.1088/2515-7639/abab6a",
language = "English",
volume = "3",
journal = "JPhys Materials",
issn = "2515-7639",
publisher = "IOP Publishing",
number = "4",

}

RIS

TY - JOUR

T1 - Spectroscopic correlation of chalcogen defects in atomically thin MoS2(1−x)Se2x alloys

AU - Sharma, Rahul

AU - Pandey, Juhi

AU - Sahoo, Krishna Rani

AU - Rana, Kewal Singh

AU - Biroju, Ravi K.

AU - Theis, Wolfgang

AU - Soni, Ajay

AU - Narayanan, Tharangattu N.

N1 - Funding Information: Authors thank support from the intramural grants at TIFR Hyderabad from the Department of Atomic Energy (DAE). RS thanks Sumit Bawari for helpful discussion about DFT calculations. Ravi K. Biroju and Wolfgang Theis acknowledge the Marie-Sklodowska-Curie individual fellowship under EU H2020 Programme (H2020-MSCA-IF-2017; Grant No: 750929) to carry out some part of this work. AS acknowledges IIT Mandi for low temperature Raman PL facilities. Publisher Copyright: © 2020 The Author(s). Published by IOP Publishing Ltd

PY - 2020/8/20

Y1 - 2020/8/20

N2 - Engineering of atomically thin transition metal dichalcogenides (TMDs) is highly sought after for novel optoelectronic and spintronic devices. With the limited number of naturally existing TMDs, chalcogen based alloying has become a viable solution for developing TMDs for optical modulators and photovoltaics. Here, we report on detailed optical and microscopic studies of ternary TMD alloys of molybdenum, sulfur, and selenium grown via a single step method. The developed material has tunable band gaps in a broad range 1.5–1.9 eV with the variation in sulfur compositions. Further, the existence of trions, bi-excitons, and defect bound excitons are shown using temperature dependent (4 K−300 K) photoluminescence spectroscopy. A detailed analysis on MoS1.34Se0.66 alloy system shows the evidence of new types of defect bound excitons originating at low temperatures along with the presence of bi-excitons having a binding energy of ∼41 meV. The prospects of defect induced quasiparticles are observed in scanning transmission electron microscope assisted analyses and verified using density functional theory calculations. The thermal conductivity values, calculated using micro-Raman studies, of MoS2, MoSe2, and MoS1.34Se0.66 are found to be 69(±2) W m−1 K−1, 33(±2) W m−1 K−1 and 17(±2) W m−1 K−1 respectively, in agreement with the theoretical predictions. Tunable optical properties of these ternary atomic layers along with moderate thermal conductivity reveal the potential of these layers in modern opto-electronic devices and sensors.

AB - Engineering of atomically thin transition metal dichalcogenides (TMDs) is highly sought after for novel optoelectronic and spintronic devices. With the limited number of naturally existing TMDs, chalcogen based alloying has become a viable solution for developing TMDs for optical modulators and photovoltaics. Here, we report on detailed optical and microscopic studies of ternary TMD alloys of molybdenum, sulfur, and selenium grown via a single step method. The developed material has tunable band gaps in a broad range 1.5–1.9 eV with the variation in sulfur compositions. Further, the existence of trions, bi-excitons, and defect bound excitons are shown using temperature dependent (4 K−300 K) photoluminescence spectroscopy. A detailed analysis on MoS1.34Se0.66 alloy system shows the evidence of new types of defect bound excitons originating at low temperatures along with the presence of bi-excitons having a binding energy of ∼41 meV. The prospects of defect induced quasiparticles are observed in scanning transmission electron microscope assisted analyses and verified using density functional theory calculations. The thermal conductivity values, calculated using micro-Raman studies, of MoS2, MoSe2, and MoS1.34Se0.66 are found to be 69(±2) W m−1 K−1, 33(±2) W m−1 K−1 and 17(±2) W m−1 K−1 respectively, in agreement with the theoretical predictions. Tunable optical properties of these ternary atomic layers along with moderate thermal conductivity reveal the potential of these layers in modern opto-electronic devices and sensors.

KW - 2D materials

KW - Bi-excitons

KW - Defect bound excitons

KW - Density functional theory

KW - Photoluminescence

KW - Thermal conductivity

KW - TMDs

UR - http://www.scopus.com/inward/record.url?scp=85092026437&partnerID=8YFLogxK

U2 - 10.1088/2515-7639/abab6a

DO - 10.1088/2515-7639/abab6a

M3 - Article

AN - SCOPUS:85092026437

VL - 3

JO - JPhys Materials

JF - JPhys Materials

SN - 2515-7639

IS - 4

M1 - 045001

ER -