Temperature-Dependent Optical Properties of Graphene on Si and SiO<sub>2</sub>/Si Substrates

Systematic investigations are performed to understand the temperature-dependent optical properties of graphene on Si and SiO<sub>2</sub>/Si substrates by using a variable angle spectroscopic ellipsometry. The optical constants of graphene have revealed changes with the substrate and temp...

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Main Authors:	Sisi Wu, Lingyu Wan, Liangmin Wei, Devki N. Talwar, Kaiyan He, Zhechuan Feng
Format:	Article
Language:	English
Published:	MDPI AG 2021-03-01
Series:	Crystals
Subjects:	graphene spectroscopic ellipsometry optical properties temperature-dependent characteristics
Online Access:	https://www.mdpi.com/2073-4352/11/4/358

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spelling	doaj-375f899a68f442cf9f69a17823cad88b2021-03-29T23:05:51ZengMDPI AGCrystals2073-43522021-03-011135835810.3390/cryst11040358Temperature-Dependent Optical Properties of Graphene on Si and SiO<sub>2</sub>/Si SubstratesSisi Wu0Lingyu Wan1Liangmin Wei2Devki N. Talwar3Kaiyan He4Zhechuan Feng5Center on Nanoenergy Research, Laboratory of Optoelectronic Materials & Detection Technology, Guangxi Key Laboratory for the Relativistic Astrophysics, School of Physical Science & Technology, Guangxi University, Nanning 530004, ChinaCenter on Nanoenergy Research, Laboratory of Optoelectronic Materials & Detection Technology, Guangxi Key Laboratory for the Relativistic Astrophysics, School of Physical Science & Technology, Guangxi University, Nanning 530004, ChinaCenter on Nanoenergy Research, Laboratory of Optoelectronic Materials & Detection Technology, Guangxi Key Laboratory for the Relativistic Astrophysics, School of Physical Science & Technology, Guangxi University, Nanning 530004, ChinaDepartment of Physics, University of North Florida, Jacksonville, FL 32224, USACenter on Nanoenergy Research, Laboratory of Optoelectronic Materials & Detection Technology, Guangxi Key Laboratory for the Relativistic Astrophysics, School of Physical Science & Technology, Guangxi University, Nanning 530004, ChinaCenter on Nanoenergy Research, Laboratory of Optoelectronic Materials & Detection Technology, Guangxi Key Laboratory for the Relativistic Astrophysics, School of Physical Science & Technology, Guangxi University, Nanning 530004, ChinaSystematic investigations are performed to understand the temperature-dependent optical properties of graphene on Si and SiO<sub>2</sub>/Si substrates by using a variable angle spectroscopic ellipsometry. The optical constants of graphene have revealed changes with the substrate and temperature. While the optical refractive index (n) of monolayer graphene on Si exhibited clear anomalous dispersions in the visible and near-infrared region (400–1200 nm), the modification is moderate for graphene on SiO<sub>2</sub>/Si substrate. Two graphene sheets have shown a pronounced absorption in the ultraviolet region with peak position related to the Van Hove singularity in the density of states. By increasing the temperature from 300 K to 500 K, for monolayer graphene on Si, the n value is gradually increased while k decreased. However, the optical constants [n, k] of monolayer graphene on SiO<sub>2</sub>/Si exhibited unpredictable wave variations. In the wavelength range of 400–1200 nm, an experiential formula of a like-Sellmeier equation is found well suited for describing the dispersions of graphene on Si and SiO<sub>2</sub>/Si substrates.https://www.mdpi.com/2073-4352/11/4/358graphenespectroscopic ellipsometryoptical propertiestemperature-dependent characteristics
collection	DOAJ
language	English
format	Article
sources	DOAJ
author	Sisi Wu Lingyu Wan Liangmin Wei Devki N. Talwar Kaiyan He Zhechuan Feng
spellingShingle	Sisi Wu Lingyu Wan Liangmin Wei Devki N. Talwar Kaiyan He Zhechuan Feng Temperature-Dependent Optical Properties of Graphene on Si and SiO<sub>2</sub>/Si Substrates Crystals graphene spectroscopic ellipsometry optical properties temperature-dependent characteristics
author_facet	Sisi Wu Lingyu Wan Liangmin Wei Devki N. Talwar Kaiyan He Zhechuan Feng
author_sort	Sisi Wu
title	Temperature-Dependent Optical Properties of Graphene on Si and SiO<sub>2</sub>/Si Substrates
title_short	Temperature-Dependent Optical Properties of Graphene on Si and SiO<sub>2</sub>/Si Substrates
title_full	Temperature-Dependent Optical Properties of Graphene on Si and SiO<sub>2</sub>/Si Substrates
title_fullStr	Temperature-Dependent Optical Properties of Graphene on Si and SiO<sub>2</sub>/Si Substrates
title_full_unstemmed	Temperature-Dependent Optical Properties of Graphene on Si and SiO<sub>2</sub>/Si Substrates
title_sort	temperature-dependent optical properties of graphene on si and sio<sub>2</sub>/si substrates
publisher	MDPI AG
series	Crystals
issn	2073-4352
publishDate	2021-03-01
description	Systematic investigations are performed to understand the temperature-dependent optical properties of graphene on Si and SiO<sub>2</sub>/Si substrates by using a variable angle spectroscopic ellipsometry. The optical constants of graphene have revealed changes with the substrate and temperature. While the optical refractive index (n) of monolayer graphene on Si exhibited clear anomalous dispersions in the visible and near-infrared region (400–1200 nm), the modification is moderate for graphene on SiO<sub>2</sub>/Si substrate. Two graphene sheets have shown a pronounced absorption in the ultraviolet region with peak position related to the Van Hove singularity in the density of states. By increasing the temperature from 300 K to 500 K, for monolayer graphene on Si, the n value is gradually increased while k decreased. However, the optical constants [n, k] of monolayer graphene on SiO<sub>2</sub>/Si exhibited unpredictable wave variations. In the wavelength range of 400–1200 nm, an experiential formula of a like-Sellmeier equation is found well suited for describing the dispersions of graphene on Si and SiO<sub>2</sub>/Si substrates.
topic	graphene spectroscopic ellipsometry optical properties temperature-dependent characteristics
url	https://www.mdpi.com/2073-4352/11/4/358
work_keys_str_mv	AT sisiwu temperaturedependentopticalpropertiesofgrapheneonsiandsiosub2subsisubstrates AT lingyuwan temperaturedependentopticalpropertiesofgrapheneonsiandsiosub2subsisubstrates AT liangminwei temperaturedependentopticalpropertiesofgrapheneonsiandsiosub2subsisubstrates AT devkintalwar temperaturedependentopticalpropertiesofgrapheneonsiandsiosub2subsisubstrates AT kaiyanhe temperaturedependentopticalpropertiesofgrapheneonsiandsiosub2subsisubstrates AT zhechuanfeng temperaturedependentopticalpropertiesofgrapheneonsiandsiosub2subsisubstrates
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Temperature-Dependent Optical Properties of Graphene on Si and SiO<sub>2</sub>/Si Substrates

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