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Yu Y, Turkowski V, Hachtel JA, Puretzky AA, Ievlev AV, Din NU, Harris SB, Iyer V, Rouleau CM, Rahman TS, Geohegan DB, Xiao K. Anomalous isotope effect on the optical bandgap in a monolayer transition metal dichalcogenide semiconductor. SCIENCE ADVANCES 2024; 10:eadj0758. [PMID: 38381831 PMCID: PMC10881028 DOI: 10.1126/sciadv.adj0758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 01/23/2024] [Indexed: 02/23/2024]
Abstract
Isotope effects have received increasing attention in materials science and engineering because altering isotopes directly affects phonons, which can affect both thermal properties and optoelectronic properties of conventional semiconductors. However, how isotopic mass affects the optoelectronic properties in 2D semiconductors remains unclear because of measurement uncertainties resulting from sample heterogeneities. Here, we report an anomalous optical bandgap energy red shift of 13 (±7) milli-electron volts as mass of Mo isotopes is increased in laterally structured 100MoS2-92MoS2 monolayers grown by a two-step chemical vapor deposition that mitigates the effects of heterogeneities. This trend, which is opposite to that observed in conventional semiconductors, is explained by many-body perturbation and time-dependent density functional theories that reveal unusually large exciton binding energy renormalizations exceeding the ground-state renormalization energy due to strong coupling between confined excitons and phonons. The isotope effect on the optical bandgap reported here provides perspective on the important role of exciton-phonon coupling in the physical properties of two-dimensional materials.
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Affiliation(s)
- Yiling Yu
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- School of Physics and Technology, Wuhan University, Wuhan 430072, China
| | - Volodymyr Turkowski
- Department of Physics, University of Central Florida, Orlando, FL 32816, USA
| | - Jordan A. Hachtel
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Alexander A. Puretzky
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Anton V. Ievlev
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Naseem U. Din
- Department of Physics, University of Central Florida, Orlando, FL 32816, USA
| | - Sumner B. Harris
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Vasudevan Iyer
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Christopher M. Rouleau
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Talat S. Rahman
- Department of Physics, University of Central Florida, Orlando, FL 32816, USA
| | - David B. Geohegan
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Kai Xiao
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
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HALLER EE. Isotopically Controlled Semiconductors. J NUCL SCI TECHNOL 2002. [DOI: 10.1080/18811248.2002.9715208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Karaiskaj D, Thewalt ML, Ruf T, Cardona M, Pohl HJ, Deviatych GG, Sennikov PG, Riemann H. Photoluminescence of isotopically purified silicon: how sharp are bound exciton transitions? PHYSICAL REVIEW LETTERS 2001; 86:6010-6013. [PMID: 11415416 DOI: 10.1103/physrevlett.86.6010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2001] [Indexed: 05/23/2023]
Abstract
We report the first high resolution photoluminescence studies of isotopically pure Si (99.896% (28)Si). New information is obtained on isotopic effects on the indirect band gap energy, phonon energies, and phonon broadenings, which is in good agreement with calculations and previous results obtained in Ge and diamond. Remarkably, the linewidths of the no-phonon boron and phosphorus bound exciton transitions in the (28)Si sample are much narrower than in natural Si and are not well resolved at our maximum instrumental resolution of approximately 0.014 cm(-1). The removal of the dominant broadening resulting from isotopic randomness in natural Si reveals new fine structure in the boron bound exciton luminescence.
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Affiliation(s)
- D Karaiskaj
- Department of Physics, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6
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Kazimirov A, Zegenhagen J, Cardona M. Isotopic mass and lattice constant: X-ray standing wave measurements. Science 1998; 282:930-2. [PMID: 9794760 DOI: 10.1126/science.282.5390.930] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The molecular volume of crystals depends on their isotopic masses. This influence originates from the zero-point motion and the resulting small differences in lattice constants. This effect was measured with high precision by using an x-ray standing wave. The standing wave is generated during Bragg reflection and thus is in phase with the planes of the substrate crystal, which is covered with a homoepitaxial film that has a different isotopic composition than the substrate. The positions of the surface planes of the film with respect to the substrate planes are revealed by the photoelectrons excited by the maxima of the standing wave. For germanium-76 on natural germanium(111), a difference in lattice constant of -1.1 x 10(-5) and -2.5 x 10(-5) at 300 and 54 kelvin, respectively, was found. The results are in good agreement with theoretical predictions.
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Affiliation(s)
- A Kazimirov
- Max-Planck-Institut fur Festkorperforschung Heisenbergstrasse 1, D-70569 Stuttgart, Germany
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Garro N, Cantarero A, Cardona M, Göbel A, Ruf T, Eberl K. Dependence of the lattice parameters and the energy gap of zinc-blende-type semiconductors on isotopic masses. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:4732-4740. [PMID: 9986433 DOI: 10.1103/physrevb.54.4732] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Plekhanov VG. Isotope-induced energy-spectrum renormalization of the Wannier-Mott exciton in LiH crystals. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:3869-3877. [PMID: 9986286 DOI: 10.1103/physrevb.54.3869] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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