Ellipsometric Surface Oxidation Model of ALD-Grown Vanadium Oxide Mixed-Valence System

Vanadium and oxygen form a complex system of vanadium oxides with multiple phases and mixed valency, increasing the difficulty of characterization. In this work, amorphous vanadium oxide thin films with mixed valence states were fabricated by atomic layer deposition, and then post-annealing was cond...

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Main Authors: Xiaojie Sun, Shuguang Wang, Qingyuan Cai, Jingze Liu, Changhai Li, Ertao Hu, Jing Li, Songyou Wang, Yuxiang Zheng, Liangyao Chen, Youngpak Lee
Format: Article
Language:English
Published: MDPI AG 2025-04-01
Series:Nanomaterials
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Online Access:https://www.mdpi.com/2079-4991/15/9/645
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author Xiaojie Sun
Shuguang Wang
Qingyuan Cai
Jingze Liu
Changhai Li
Ertao Hu
Jing Li
Songyou Wang
Yuxiang Zheng
Liangyao Chen
Youngpak Lee
author_facet Xiaojie Sun
Shuguang Wang
Qingyuan Cai
Jingze Liu
Changhai Li
Ertao Hu
Jing Li
Songyou Wang
Yuxiang Zheng
Liangyao Chen
Youngpak Lee
author_sort Xiaojie Sun
collection DOAJ
description Vanadium and oxygen form a complex system of vanadium oxides with multiple phases and mixed valency, increasing the difficulty of characterization. In this work, amorphous vanadium oxide thin films with mixed valence states were fabricated by atomic layer deposition, and then post-annealing was conducted for crystalline films. For the surface analysis of this mixed-valence system, X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES) were employed. However, XPS is only able to quasi-quantitatively determine the surface-proximity oxidation states. To account for the inadequacy of surface-sensitive XPS and AES techniques, a surface oxidation model (SOM) was proposed for the ellipsometric modeling of the mixed-valence system. Furthermore, by conducting air thermal oxidation (ATO) experiments, the four sets of fitting parameters of SOM were decreased to three, lowering the system complexity. This study is expected to help with the analysis of vanadium oxide mixed-valence systems and other multivalent metal oxide systems.
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institution DOAJ
issn 2079-4991
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publishDate 2025-04-01
publisher MDPI AG
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series Nanomaterials
spelling doaj-art-686fbad1555a4060815204703bc77b932025-08-20T02:59:15ZengMDPI AGNanomaterials2079-49912025-04-0115964510.3390/nano15090645Ellipsometric Surface Oxidation Model of ALD-Grown Vanadium Oxide Mixed-Valence SystemXiaojie Sun0Shuguang Wang1Qingyuan Cai2Jingze Liu3Changhai Li4Ertao Hu5Jing Li6Songyou Wang7Yuxiang Zheng8Liangyao Chen9Youngpak Lee10State Key Laboratory of Photovoltaic Science and Technology, Department of Optical Science and Engineering, School of Information Science and Technology, Fudan University, Shanghai 200433, ChinaState Key Laboratory of Photovoltaic Science and Technology, Department of Optical Science and Engineering, School of Information Science and Technology, Fudan University, Shanghai 200433, ChinaShanghai Key Laboratory of Optical Coatings and Spectral Modulation, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, ChinaState Key Laboratory of Photovoltaic Science and Technology, Department of Optical Science and Engineering, School of Information Science and Technology, Fudan University, Shanghai 200433, ChinaState Key Laboratory of Photovoltaic Science and Technology, Department of Optical Science and Engineering, School of Information Science and Technology, Fudan University, Shanghai 200433, ChinaCollege of Electronic and Optical Engineering, Nanjing University of Posts and Telecommunications, Nanjing 210023, ChinaState Key Laboratory of Photovoltaic Science and Technology, Department of Optical Science and Engineering, School of Information Science and Technology, Fudan University, Shanghai 200433, ChinaState Key Laboratory of Photovoltaic Science and Technology, Department of Optical Science and Engineering, School of Information Science and Technology, Fudan University, Shanghai 200433, ChinaState Key Laboratory of Photovoltaic Science and Technology, Department of Optical Science and Engineering, School of Information Science and Technology, Fudan University, Shanghai 200433, ChinaState Key Laboratory of Photovoltaic Science and Technology, Department of Optical Science and Engineering, School of Information Science and Technology, Fudan University, Shanghai 200433, ChinaState Key Laboratory of Photovoltaic Science and Technology, Department of Optical Science and Engineering, School of Information Science and Technology, Fudan University, Shanghai 200433, ChinaVanadium and oxygen form a complex system of vanadium oxides with multiple phases and mixed valency, increasing the difficulty of characterization. In this work, amorphous vanadium oxide thin films with mixed valence states were fabricated by atomic layer deposition, and then post-annealing was conducted for crystalline films. For the surface analysis of this mixed-valence system, X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES) were employed. However, XPS is only able to quasi-quantitatively determine the surface-proximity oxidation states. To account for the inadequacy of surface-sensitive XPS and AES techniques, a surface oxidation model (SOM) was proposed for the ellipsometric modeling of the mixed-valence system. Furthermore, by conducting air thermal oxidation (ATO) experiments, the four sets of fitting parameters of SOM were decreased to three, lowering the system complexity. This study is expected to help with the analysis of vanadium oxide mixed-valence systems and other multivalent metal oxide systems.https://www.mdpi.com/2079-4991/15/9/645vanadium oxidesmixed-valence systemsurface oxidationoptical thin filmatomic layer depositionspectroscopic ellipsometry
spellingShingle Xiaojie Sun
Shuguang Wang
Qingyuan Cai
Jingze Liu
Changhai Li
Ertao Hu
Jing Li
Songyou Wang
Yuxiang Zheng
Liangyao Chen
Youngpak Lee
Ellipsometric Surface Oxidation Model of ALD-Grown Vanadium Oxide Mixed-Valence System
Nanomaterials
vanadium oxides
mixed-valence system
surface oxidation
optical thin film
atomic layer deposition
spectroscopic ellipsometry
title Ellipsometric Surface Oxidation Model of ALD-Grown Vanadium Oxide Mixed-Valence System
title_full Ellipsometric Surface Oxidation Model of ALD-Grown Vanadium Oxide Mixed-Valence System
title_fullStr Ellipsometric Surface Oxidation Model of ALD-Grown Vanadium Oxide Mixed-Valence System
title_full_unstemmed Ellipsometric Surface Oxidation Model of ALD-Grown Vanadium Oxide Mixed-Valence System
title_short Ellipsometric Surface Oxidation Model of ALD-Grown Vanadium Oxide Mixed-Valence System
title_sort ellipsometric surface oxidation model of ald grown vanadium oxide mixed valence system
topic vanadium oxides
mixed-valence system
surface oxidation
optical thin film
atomic layer deposition
spectroscopic ellipsometry
url https://www.mdpi.com/2079-4991/15/9/645
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AT jingzeliu ellipsometricsurfaceoxidationmodelofaldgrownvanadiumoxidemixedvalencesystem
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