Soft X-ray spectroscopic study on the electronic structure of WO3 thin films fabricated under various annealing temperature and gas flow conditions

Yoo Kyung Park; Chang Jin Lim; Yeong Ji Im; Soohaeng Cho; Sang Wan Cho; Hyunbok Lee; Hirohito Ogasawara

doi:10.1016/j.cap.2020.10.006

Soft X-ray spectroscopic study on the electronic structure of WO₃ thin films fabricated under various annealing temperature and gas flow conditions

Yoo Kyung Park, Chang Jin Lim, Yeong Ji Im, Soohaeng Cho, Sang Wan Cho, Hyunbok Lee, Hirohito Ogasawara

Physics

Research output: Contribution to journal › Article › peer-review

6 Citations (Scopus)

Abstract

The electrical properties of WO₃ thin films vary significantly depending on the growth conditions. In this work, the influence of O₂ gas on the band gap of WO₃ thin films during growth was investigated via electronic structure characterization using X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS), and X-ray emission spectroscopy (XES). A substantial decrease in the electrical conductivity of the WO₃ films was observed with an increase in the O₂ partial pressure during growth. Spectral differences in the peak energy and intensity were apparent for WO₃ films grown under only Ar and those grown in Ar:O₂. It is difficult to explain the acquired spectrum of WO₃ with oxygen defects through the rigid-band model in terms of the simple addition of electrons to the conduction band of WO₃. Our results show that an oxygen deficiency in WO₃ moves the conduction band to the Fermi edge.

Original language	English
Pages (from-to)	31-35
Number of pages	5
Journal	Current Applied Physics
Volume	21
DOIs	https://doi.org/10.1016/j.cap.2020.10.006
Publication status	Published - 2021 Jan

Bibliographical note

Funding Information:
This work was supported by a research project of the National Research Foundation of Korea (Grant No. 2017R1D1A3B03034867 ) and the Yonsei University Future-leading Research Initiative (Grant No. 2017-52-0071 ). Part of this study was carried out at the Stanford Synchrotron Radiation Lightsource, a National User Facility operated by Stanford University on behalf of the Basic Energy Sciences, U.S. Department of Energy.

Funding Information:
This work was supported by a research project of the National Research Foundation of Korea (Grant No. 2017R1D1A3B03034867) and the Yonsei University Future-leading Research Initiative (Grant No. 2017-52-0071). Part of this study was carried out at the Stanford Synchrotron Radiation Lightsource, a National User Facility operated by Stanford University on behalf of the Basic Energy Sciences, U.S. Department of Energy.

Publisher Copyright:
© 2020 Korean Physical Society

All Science Journal Classification (ASJC) codes

Materials Science(all)
Physics and Astronomy(all)

Access to Document

10.1016/j.cap.2020.10.006

Cite this

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title = "Soft X-ray spectroscopic study on the electronic structure of WO3 thin films fabricated under various annealing temperature and gas flow conditions",

abstract = "The electrical properties of WO3 thin films vary significantly depending on the growth conditions. In this work, the influence of O2 gas on the band gap of WO3 thin films during growth was investigated via electronic structure characterization using X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS), and X-ray emission spectroscopy (XES). A substantial decrease in the electrical conductivity of the WO3 films was observed with an increase in the O2 partial pressure during growth. Spectral differences in the peak energy and intensity were apparent for WO3 films grown under only Ar and those grown in Ar:O2. It is difficult to explain the acquired spectrum of WO3 with oxygen defects through the rigid-band model in terms of the simple addition of electrons to the conduction band of WO3. Our results show that an oxygen deficiency in WO3 moves the conduction band to the Fermi edge.",

author = "Park, {Yoo Kyung} and Lim, {Chang Jin} and Im, {Yeong Ji} and Soohaeng Cho and Cho, {Sang Wan} and Hyunbok Lee and Hirohito Ogasawara",

note = "Funding Information: This work was supported by a research project of the National Research Foundation of Korea (Grant No. 2017R1D1A3B03034867 ) and the Yonsei University Future-leading Research Initiative (Grant No. 2017-52-0071 ). Part of this study was carried out at the Stanford Synchrotron Radiation Lightsource, a National User Facility operated by Stanford University on behalf of the Basic Energy Sciences, U.S. Department of Energy. Funding Information: This work was supported by a research project of the National Research Foundation of Korea (Grant No. 2017R1D1A3B03034867) and the Yonsei University Future-leading Research Initiative (Grant No. 2017-52-0071). Part of this study was carried out at the Stanford Synchrotron Radiation Lightsource, a National User Facility operated by Stanford University on behalf of the Basic Energy Sciences, U.S. Department of Energy. Publisher Copyright: {\textcopyright} 2020 Korean Physical Society",

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AU - Park, Yoo Kyung

AU - Lim, Chang Jin

AU - Im, Yeong Ji

AU - Cho, Soohaeng

AU - Cho, Sang Wan

AU - Lee, Hyunbok

AU - Ogasawara, Hirohito

N1 - Funding Information: This work was supported by a research project of the National Research Foundation of Korea (Grant No. 2017R1D1A3B03034867 ) and the Yonsei University Future-leading Research Initiative (Grant No. 2017-52-0071 ). Part of this study was carried out at the Stanford Synchrotron Radiation Lightsource, a National User Facility operated by Stanford University on behalf of the Basic Energy Sciences, U.S. Department of Energy. Funding Information: This work was supported by a research project of the National Research Foundation of Korea (Grant No. 2017R1D1A3B03034867) and the Yonsei University Future-leading Research Initiative (Grant No. 2017-52-0071). Part of this study was carried out at the Stanford Synchrotron Radiation Lightsource, a National User Facility operated by Stanford University on behalf of the Basic Energy Sciences, U.S. Department of Energy. Publisher Copyright: © 2020 Korean Physical Society

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N2 - The electrical properties of WO3 thin films vary significantly depending on the growth conditions. In this work, the influence of O2 gas on the band gap of WO3 thin films during growth was investigated via electronic structure characterization using X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS), and X-ray emission spectroscopy (XES). A substantial decrease in the electrical conductivity of the WO3 films was observed with an increase in the O2 partial pressure during growth. Spectral differences in the peak energy and intensity were apparent for WO3 films grown under only Ar and those grown in Ar:O2. It is difficult to explain the acquired spectrum of WO3 with oxygen defects through the rigid-band model in terms of the simple addition of electrons to the conduction band of WO3. Our results show that an oxygen deficiency in WO3 moves the conduction band to the Fermi edge.

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