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Optical Contrast and Raman Spectroscopy Techniques Applied to Few-Layer 2D Hexagonal Boron Nitride

The successful integration of few-layer thick hexagonal boron nitride (hBN) into devices based on two-dimensional materials requires fast and non-destructive techniques to quantify their thickness. Optical contrast methods and Raman spectroscopy have been widely used to estimate the thickness of two...

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Autores principales: Krečmarová, Marie, Andres-Penares, Daniel, Fekete, Ladislav, Ashcheulov, Petr, Molina-Sánchez, Alejandro, Canet-Albiach, Rodolfo, Gregora, Ivan, Mortet, Vincent, Martínez-Pastor, Juan P., Sánchez-Royo, Juan F.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6669639/
https://www.ncbi.nlm.nih.gov/pubmed/31336572
http://dx.doi.org/10.3390/nano9071047
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author Krečmarová, Marie
Andres-Penares, Daniel
Fekete, Ladislav
Ashcheulov, Petr
Molina-Sánchez, Alejandro
Canet-Albiach, Rodolfo
Gregora, Ivan
Mortet, Vincent
Martínez-Pastor, Juan P.
Sánchez-Royo, Juan F.
author_facet Krečmarová, Marie
Andres-Penares, Daniel
Fekete, Ladislav
Ashcheulov, Petr
Molina-Sánchez, Alejandro
Canet-Albiach, Rodolfo
Gregora, Ivan
Mortet, Vincent
Martínez-Pastor, Juan P.
Sánchez-Royo, Juan F.
author_sort Krečmarová, Marie
collection PubMed
description The successful integration of few-layer thick hexagonal boron nitride (hBN) into devices based on two-dimensional materials requires fast and non-destructive techniques to quantify their thickness. Optical contrast methods and Raman spectroscopy have been widely used to estimate the thickness of two-dimensional semiconductors and semi-metals. However, they have so far not been applied to two-dimensional insulators. In this work, we demonstrate the ability of optical contrast techniques to estimate the thickness of few-layer hBN on SiO(2)/Si substrates, which was also measured by atomic force microscopy. Optical contrast of hBN on SiO(2)/Si substrates exhibits a linear trend with the number of hBN monolayers in the few-layer thickness range. We also used bandpass filters (500–650 nm) to improve the effectiveness of the optical contrast methods for thickness estimations. We also investigated the thickness dependence of the high frequency in-plane E(2g) phonon mode of atomically thin hBN on SiO(2)/Si substrates by micro-Raman spectroscopy, which exhibits a weak thickness-dependence attributable to the in-plane vibration character of this mode. Ab initio calculations of the Raman active phonon modes of atomically thin free-standing crystals support these results, even if the substrate can reduce the frequency shift of the E(2g) phonon mode by reducing the hBN thickness. Therefore, the optical contrast method arises as the most suitable and fast technique to estimate the thickness of hBN nanosheets.
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spelling pubmed-66696392019-08-08 Optical Contrast and Raman Spectroscopy Techniques Applied to Few-Layer 2D Hexagonal Boron Nitride Krečmarová, Marie Andres-Penares, Daniel Fekete, Ladislav Ashcheulov, Petr Molina-Sánchez, Alejandro Canet-Albiach, Rodolfo Gregora, Ivan Mortet, Vincent Martínez-Pastor, Juan P. Sánchez-Royo, Juan F. Nanomaterials (Basel) Article The successful integration of few-layer thick hexagonal boron nitride (hBN) into devices based on two-dimensional materials requires fast and non-destructive techniques to quantify their thickness. Optical contrast methods and Raman spectroscopy have been widely used to estimate the thickness of two-dimensional semiconductors and semi-metals. However, they have so far not been applied to two-dimensional insulators. In this work, we demonstrate the ability of optical contrast techniques to estimate the thickness of few-layer hBN on SiO(2)/Si substrates, which was also measured by atomic force microscopy. Optical contrast of hBN on SiO(2)/Si substrates exhibits a linear trend with the number of hBN monolayers in the few-layer thickness range. We also used bandpass filters (500–650 nm) to improve the effectiveness of the optical contrast methods for thickness estimations. We also investigated the thickness dependence of the high frequency in-plane E(2g) phonon mode of atomically thin hBN on SiO(2)/Si substrates by micro-Raman spectroscopy, which exhibits a weak thickness-dependence attributable to the in-plane vibration character of this mode. Ab initio calculations of the Raman active phonon modes of atomically thin free-standing crystals support these results, even if the substrate can reduce the frequency shift of the E(2g) phonon mode by reducing the hBN thickness. Therefore, the optical contrast method arises as the most suitable and fast technique to estimate the thickness of hBN nanosheets. MDPI 2019-07-22 /pmc/articles/PMC6669639/ /pubmed/31336572 http://dx.doi.org/10.3390/nano9071047 Text en © 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Krečmarová, Marie
Andres-Penares, Daniel
Fekete, Ladislav
Ashcheulov, Petr
Molina-Sánchez, Alejandro
Canet-Albiach, Rodolfo
Gregora, Ivan
Mortet, Vincent
Martínez-Pastor, Juan P.
Sánchez-Royo, Juan F.
Optical Contrast and Raman Spectroscopy Techniques Applied to Few-Layer 2D Hexagonal Boron Nitride
title Optical Contrast and Raman Spectroscopy Techniques Applied to Few-Layer 2D Hexagonal Boron Nitride
title_full Optical Contrast and Raman Spectroscopy Techniques Applied to Few-Layer 2D Hexagonal Boron Nitride
title_fullStr Optical Contrast and Raman Spectroscopy Techniques Applied to Few-Layer 2D Hexagonal Boron Nitride
title_full_unstemmed Optical Contrast and Raman Spectroscopy Techniques Applied to Few-Layer 2D Hexagonal Boron Nitride
title_short Optical Contrast and Raman Spectroscopy Techniques Applied to Few-Layer 2D Hexagonal Boron Nitride
title_sort optical contrast and raman spectroscopy techniques applied to few-layer 2d hexagonal boron nitride
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6669639/
https://www.ncbi.nlm.nih.gov/pubmed/31336572
http://dx.doi.org/10.3390/nano9071047
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