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Title: Probing the Optical Properties and Strain-Tuning of Ultrathin Mo 1–xW xTe 2

Ultrathin transition metal dichalcogenides (TMDCs) have recently been extensively investigated to understand their electronic and optical properties. Here we study ultrathin Mo 0.91W 0.09Te 2, a semiconducting alloy of MoTe 2, using Raman, photoluminescence (PL), and optical absorption spectroscopy. Mo 0.91W 0.09Te 2 transitions from an indirect to a direct optical band gap in the limit of monolayer thickness, exhibiting an optical gap of 1.10 eV, very close to its MoTe 2 counterpart. We apply tensile strain, for the first time, to monolayer MoTe 2 and Mo 0.91W 0.09Te 2 to tune the band structure of these materials; we observe that their optical band gaps decrease by 70 meV at 2.3% uniaxial strain. The spectral widths of the PL peaks decrease with increasing strain, which we attribute to weaker exciton–phonon intervalley scattering. Furthermore, strained MoTe 2 and Mo 0.91W 0.09Te 2 extend the range of band gaps of TMDC monolayers further into the near-infrared, an important attribute for potential applications in optoelectronics.
Authors:
ORCiD logo [1] ;  [2] ;  [2] ;  [2] ;  [3] ;  [4] ; ORCiD logo [4] ;  [4] ; ORCiD logo [2] ; ORCiD logo [1]
  1. Stanford Univ., Stanford, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States)
  2. Stanford Univ., Stanford, CA (United States)
  3. National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States); Theiss Research, La Jolla, CA (United States)
  4. National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States)
Publication Date:
Grant/Contract Number:
AC02-76SF00515; W911NF-15-1-0570; 70NANB16H043; FA9550-14-1-0040; FA9550-14-1-0251; 1542883
Type:
Accepted Manuscript
Journal Name:
Nano Letters
Additional Journal Information:
Journal Volume: 18; Journal Issue: 4; Journal ID: ISSN 1530-6984
Publisher:
American Chemical Society
Research Org:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; alloyed 2D materials; band gap; MoTe2; MoWTe2; photoluminescence; strain engineering
OSTI Identifier:
1457055

Aslan, Ozgur Burak, Datye, Isha M., Mleczko, Michal J., Cheung, Karen Sze, Krylyuk, Sergiy, Bruma, Alina, Kalish, Irina, Davydov, Albert V., Pop, Eric, and Heinz, Tony F.. Probing the Optical Properties and Strain-Tuning of Ultrathin Mo1–xWxTe2. United States: N. p., Web. doi:10.1021/acs.nanolett.8b00049.
Aslan, Ozgur Burak, Datye, Isha M., Mleczko, Michal J., Cheung, Karen Sze, Krylyuk, Sergiy, Bruma, Alina, Kalish, Irina, Davydov, Albert V., Pop, Eric, & Heinz, Tony F.. Probing the Optical Properties and Strain-Tuning of Ultrathin Mo1–xWxTe2. United States. doi:10.1021/acs.nanolett.8b00049.
Aslan, Ozgur Burak, Datye, Isha M., Mleczko, Michal J., Cheung, Karen Sze, Krylyuk, Sergiy, Bruma, Alina, Kalish, Irina, Davydov, Albert V., Pop, Eric, and Heinz, Tony F.. 2018. "Probing the Optical Properties and Strain-Tuning of Ultrathin Mo1–xWxTe2". United States. doi:10.1021/acs.nanolett.8b00049.
@article{osti_1457055,
title = {Probing the Optical Properties and Strain-Tuning of Ultrathin Mo1–xWxTe2},
author = {Aslan, Ozgur Burak and Datye, Isha M. and Mleczko, Michal J. and Cheung, Karen Sze and Krylyuk, Sergiy and Bruma, Alina and Kalish, Irina and Davydov, Albert V. and Pop, Eric and Heinz, Tony F.},
abstractNote = {Ultrathin transition metal dichalcogenides (TMDCs) have recently been extensively investigated to understand their electronic and optical properties. Here we study ultrathin Mo0.91W0.09Te2, a semiconducting alloy of MoTe2, using Raman, photoluminescence (PL), and optical absorption spectroscopy. Mo0.91W0.09Te2 transitions from an indirect to a direct optical band gap in the limit of monolayer thickness, exhibiting an optical gap of 1.10 eV, very close to its MoTe2 counterpart. We apply tensile strain, for the first time, to monolayer MoTe2 and Mo0.91W0.09Te2 to tune the band structure of these materials; we observe that their optical band gaps decrease by 70 meV at 2.3% uniaxial strain. The spectral widths of the PL peaks decrease with increasing strain, which we attribute to weaker exciton–phonon intervalley scattering. Furthermore, strained MoTe2 and Mo0.91W0.09Te2 extend the range of band gaps of TMDC monolayers further into the near-infrared, an important attribute for potential applications in optoelectronics.},
doi = {10.1021/acs.nanolett.8b00049},
journal = {Nano Letters},
number = 4,
volume = 18,
place = {United States},
year = {2018},
month = {3}
}