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High-Temperature Molecular Beam Epitaxy of Hexagonal Boron Nitride with High Active Nitrogen Fluxes

Hexagonal boron nitride (hBN) has attracted a great deal of attention as a key component in van der Waals (vdW) heterostructures, and as a wide band gap material for deep-ultraviolet devices. We have recently demonstrated plasma-assisted molecular beam epitaxy (PA-MBE) of hBN layers on substrates of...

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Autores principales: Cheng, Tin S., Summerfield, Alex, Mellor, Christopher J., Khlobystov, Andrei N., Eaves, Laurence, Foxon, C. Thomas, Beton, Peter H., Novikov, Sergei V.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6073546/
https://www.ncbi.nlm.nih.gov/pubmed/29966333
http://dx.doi.org/10.3390/ma11071119
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author Cheng, Tin S.
Summerfield, Alex
Mellor, Christopher J.
Khlobystov, Andrei N.
Eaves, Laurence
Foxon, C. Thomas
Beton, Peter H.
Novikov, Sergei V.
author_facet Cheng, Tin S.
Summerfield, Alex
Mellor, Christopher J.
Khlobystov, Andrei N.
Eaves, Laurence
Foxon, C. Thomas
Beton, Peter H.
Novikov, Sergei V.
author_sort Cheng, Tin S.
collection PubMed
description Hexagonal boron nitride (hBN) has attracted a great deal of attention as a key component in van der Waals (vdW) heterostructures, and as a wide band gap material for deep-ultraviolet devices. We have recently demonstrated plasma-assisted molecular beam epitaxy (PA-MBE) of hBN layers on substrates of highly oriented pyrolytic graphite at high substrate temperatures of ~1400 °C. The current paper will present data on the high-temperature PA-MBE growth of hBN layers using a high-efficiency radio-frequency (RF) nitrogen plasma source. Despite more than a three-fold increase in nitrogen flux with this new source, we saw no significant increase in the growth rates of the hBN layers, indicating that the growth rate of hBN layers is controlled by the boron arrival rate. The hBN thickness increases to 90 nm with decrease in the growth temperature to 1080 °C. However, the decrease in the MBE temperature led to a deterioration in the optical properties of the hBN. The optical absorption data indicates that an increase in the active nitrogen flux during the PA-MBE process improves the optical properties of hBN and suppresses defect related optical absorption in the energy range 5.0–5.5 eV.
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spelling pubmed-60735462018-08-13 High-Temperature Molecular Beam Epitaxy of Hexagonal Boron Nitride with High Active Nitrogen Fluxes Cheng, Tin S. Summerfield, Alex Mellor, Christopher J. Khlobystov, Andrei N. Eaves, Laurence Foxon, C. Thomas Beton, Peter H. Novikov, Sergei V. Materials (Basel) Article Hexagonal boron nitride (hBN) has attracted a great deal of attention as a key component in van der Waals (vdW) heterostructures, and as a wide band gap material for deep-ultraviolet devices. We have recently demonstrated plasma-assisted molecular beam epitaxy (PA-MBE) of hBN layers on substrates of highly oriented pyrolytic graphite at high substrate temperatures of ~1400 °C. The current paper will present data on the high-temperature PA-MBE growth of hBN layers using a high-efficiency radio-frequency (RF) nitrogen plasma source. Despite more than a three-fold increase in nitrogen flux with this new source, we saw no significant increase in the growth rates of the hBN layers, indicating that the growth rate of hBN layers is controlled by the boron arrival rate. The hBN thickness increases to 90 nm with decrease in the growth temperature to 1080 °C. However, the decrease in the MBE temperature led to a deterioration in the optical properties of the hBN. The optical absorption data indicates that an increase in the active nitrogen flux during the PA-MBE process improves the optical properties of hBN and suppresses defect related optical absorption in the energy range 5.0–5.5 eV. MDPI 2018-06-30 /pmc/articles/PMC6073546/ /pubmed/29966333 http://dx.doi.org/10.3390/ma11071119 Text en © 2018 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
Cheng, Tin S.
Summerfield, Alex
Mellor, Christopher J.
Khlobystov, Andrei N.
Eaves, Laurence
Foxon, C. Thomas
Beton, Peter H.
Novikov, Sergei V.
High-Temperature Molecular Beam Epitaxy of Hexagonal Boron Nitride with High Active Nitrogen Fluxes
title High-Temperature Molecular Beam Epitaxy of Hexagonal Boron Nitride with High Active Nitrogen Fluxes
title_full High-Temperature Molecular Beam Epitaxy of Hexagonal Boron Nitride with High Active Nitrogen Fluxes
title_fullStr High-Temperature Molecular Beam Epitaxy of Hexagonal Boron Nitride with High Active Nitrogen Fluxes
title_full_unstemmed High-Temperature Molecular Beam Epitaxy of Hexagonal Boron Nitride with High Active Nitrogen Fluxes
title_short High-Temperature Molecular Beam Epitaxy of Hexagonal Boron Nitride with High Active Nitrogen Fluxes
title_sort high-temperature molecular beam epitaxy of hexagonal boron nitride with high active nitrogen fluxes
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6073546/
https://www.ncbi.nlm.nih.gov/pubmed/29966333
http://dx.doi.org/10.3390/ma11071119
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