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Temperature Dependence of the Dielectric Function of Monolayer MoSe(2)

The dielectric function [Formula: see text] of monolayer molybdenum diselenide (MoSe(2)) is obtained and analyzed at temperatures from 31 to 300 K and at energies from 0.74 to 6.42 eV. The sample is a large-area, partially discontinuous monolayer (submonolayer) film of MoSe(2) grown on a sapphire su...

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Autores principales: Park, Han Gyeol, Kim, Tae Jung, Ullah, Farman, Le, Van Long, Nguyen, Hoang Tung, Kim, Yong Soo, Kim, Young Dong
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group UK 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5816670/
https://www.ncbi.nlm.nih.gov/pubmed/29453397
http://dx.doi.org/10.1038/s41598-018-21508-5
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author Park, Han Gyeol
Kim, Tae Jung
Ullah, Farman
Le, Van Long
Nguyen, Hoang Tung
Kim, Yong Soo
Kim, Young Dong
author_facet Park, Han Gyeol
Kim, Tae Jung
Ullah, Farman
Le, Van Long
Nguyen, Hoang Tung
Kim, Yong Soo
Kim, Young Dong
author_sort Park, Han Gyeol
collection PubMed
description The dielectric function [Formula: see text] of monolayer molybdenum diselenide (MoSe(2)) is obtained and analyzed at temperatures from 31 to 300 K and at energies from 0.74 to 6.42 eV. The sample is a large-area, partially discontinuous monolayer (submonolayer) film of MoSe(2) grown on a sapphire substrate by selenization of pulsed laser deposited MoO(3) film. Morphological and optical characterizations verified the excellent quality of the film. The MoSe(2) data were analyzed using the effective medium approximation, which treats the film and bare substrate regions as a single layer. Second derivatives of ε with respect to energy were numerically calculated and analyzed with standard lineshapes to extract accurate critical-point (CP) energies. We find only 6 CPs for monolayer MoSe(2) at room temperature. At cryogenic temperatures 6 additional structures are resolved. The separations in the B- and C-excitonic peaks are also observed. All structures blue-shift and sharpen with decreasing temperature as a result of the reducing lattice constant and electron-phonon interactions. The temperature dependences of the CP energies were determined by fitting the data to the phenomenological expression that contains the Bose-Einstein statistical factor and the temperature coefficient.
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spelling pubmed-58166702018-02-21 Temperature Dependence of the Dielectric Function of Monolayer MoSe(2) Park, Han Gyeol Kim, Tae Jung Ullah, Farman Le, Van Long Nguyen, Hoang Tung Kim, Yong Soo Kim, Young Dong Sci Rep Article The dielectric function [Formula: see text] of monolayer molybdenum diselenide (MoSe(2)) is obtained and analyzed at temperatures from 31 to 300 K and at energies from 0.74 to 6.42 eV. The sample is a large-area, partially discontinuous monolayer (submonolayer) film of MoSe(2) grown on a sapphire substrate by selenization of pulsed laser deposited MoO(3) film. Morphological and optical characterizations verified the excellent quality of the film. The MoSe(2) data were analyzed using the effective medium approximation, which treats the film and bare substrate regions as a single layer. Second derivatives of ε with respect to energy were numerically calculated and analyzed with standard lineshapes to extract accurate critical-point (CP) energies. We find only 6 CPs for monolayer MoSe(2) at room temperature. At cryogenic temperatures 6 additional structures are resolved. The separations in the B- and C-excitonic peaks are also observed. All structures blue-shift and sharpen with decreasing temperature as a result of the reducing lattice constant and electron-phonon interactions. The temperature dependences of the CP energies were determined by fitting the data to the phenomenological expression that contains the Bose-Einstein statistical factor and the temperature coefficient. Nature Publishing Group UK 2018-02-16 /pmc/articles/PMC5816670/ /pubmed/29453397 http://dx.doi.org/10.1038/s41598-018-21508-5 Text en © The Author(s) 2018 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.
spellingShingle Article
Park, Han Gyeol
Kim, Tae Jung
Ullah, Farman
Le, Van Long
Nguyen, Hoang Tung
Kim, Yong Soo
Kim, Young Dong
Temperature Dependence of the Dielectric Function of Monolayer MoSe(2)
title Temperature Dependence of the Dielectric Function of Monolayer MoSe(2)
title_full Temperature Dependence of the Dielectric Function of Monolayer MoSe(2)
title_fullStr Temperature Dependence of the Dielectric Function of Monolayer MoSe(2)
title_full_unstemmed Temperature Dependence of the Dielectric Function of Monolayer MoSe(2)
title_short Temperature Dependence of the Dielectric Function of Monolayer MoSe(2)
title_sort temperature dependence of the dielectric function of monolayer mose(2)
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5816670/
https://www.ncbi.nlm.nih.gov/pubmed/29453397
http://dx.doi.org/10.1038/s41598-018-21508-5
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