Defect-Engineered VO 2 Films: From Abrupt Phase Transition to Continuous Infrared Modulation via High-Vacuum Annealing.
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| Title: | Defect-Engineered VO 2 Films: From Abrupt Phase Transition to Continuous Infrared Modulation via High-Vacuum Annealing. |
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| Authors: | Liu, Lin1 (AUTHOR), Li, Jinxiao1 (AUTHOR), Wu, Lei1 (AUTHOR), Wu, Xiaoling1 (AUTHOR), Cheng, Guoan1 (AUTHOR) gacheng@bnu.edu.cn, Zheng, Ruiting (AUTHOR) rtzheng@bnu.edu.cn |
| Source: | Nanomaterials (2079-4991). May2026, Vol. 16 Issue 10, p575. 14p. |
| Subjects: | Oxygen vacancy, Annealing of metals, Optical modulation, Electrochromic windows, Metal-insulator transitions, Phase transitions, Vanadium dioxide |
| Abstract: | Vanadium dioxide (VO2) films have attracted extensive attention for their pronounced metal–insulator transition (MIT) and multifunctional responses, holding great promise for smart windows, infrared stealth, memristive devices, and advanced sensors. However, conventional approaches for tuning the transition temperature, such as elemental doping or heterostructure engineering, often suffer from complicated processing, impurity phases, and poor device uniformity. Here, we use a dopant-free, high-vacuum annealing (9 × 10−4 Pa, ≈9 × 10−6 mbar) strategy to regulate the intrinsic structural evolution of VO2 films via oxygen-vacancy engineering and to clarify its influence on electrical switching contrast and infrared emissivity modulation. As the annealing temperature increases under low oxygen partial pressure, oxygen vacancies gradually accumulate, converting V4+ to V3+ and driving the films through three distinct structural stages: low-temperature lattice expansion with preserved M1 framework, critical structural collapse at 550 °C, and high-temperature defect rearrangement with local recrystallization. Consequently, the electrical MIT temperature continuously decreases, but the switching ratio collapses at the critical point and only partially recovers after high-temperature reorganization, while the infrared emissivity response transitions from abrupt, phase-transition-dominated switching to a continuous, tunable modulation at elevated temperatures. Notably, the infrared response begins continuous tuning earlier (≈450 °C) than the collapse of electrical MIT, reflecting the different sensitivities of optical and electronic responses to local lattice defects. These results reveal the coupling among oxygen-vacancy evolution, structural stability, electrical contrast, and infrared modulation in compositionally simple VO2 films. Compared with conventional doping, this high-vacuum annealing strategy avoids impurity phases, preserves compositional simplicity, and provides a scalable defect-engineering route to design VO2-based devices with reconfigurable electrical and infrared response modes. [ABSTRACT FROM AUTHOR] |
| Copyright of Nanomaterials (2079-4991) is the property of MDPI and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
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| Header | DbId: egs DbLabel: Engineering Source An: 194120557 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Defect-Engineered VO 2 Films: From Abrupt Phase Transition to Continuous Infrared Modulation via High-Vacuum Annealing. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Liu%2C+Lin%22">Liu, Lin</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Li%2C+Jinxiao%22">Li, Jinxiao</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Wu%2C+Lei%22">Wu, Lei</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Wu%2C+Xiaoling%22">Wu, Xiaoling</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Cheng%2C+Guoan%22">Cheng, Guoan</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> gacheng@bnu.edu.cn</i><br /><searchLink fieldCode="AR" term="%22Zheng%2C+Ruiting%22">Zheng, Ruiting</searchLink> (AUTHOR)<i> rtzheng@bnu.edu.cn</i> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Nanomaterials+%282079-4991%29%22">Nanomaterials (2079-4991)</searchLink>. May2026, Vol. 16 Issue 10, p575. 14p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Oxygen+vacancy%22">Oxygen vacancy</searchLink><br /><searchLink fieldCode="DE" term="%22Annealing+of+metals%22">Annealing of metals</searchLink><br /><searchLink fieldCode="DE" term="%22Optical+modulation%22">Optical modulation</searchLink><br /><searchLink fieldCode="DE" term="%22Electrochromic+windows%22">Electrochromic windows</searchLink><br /><searchLink fieldCode="DE" term="%22Metal-insulator+transitions%22">Metal-insulator transitions</searchLink><br /><searchLink fieldCode="DE" term="%22Phase+transitions%22">Phase transitions</searchLink><br /><searchLink fieldCode="DE" term="%22Vanadium+dioxide%22">Vanadium dioxide</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Vanadium dioxide (VO2) films have attracted extensive attention for their pronounced metal–insulator transition (MIT) and multifunctional responses, holding great promise for smart windows, infrared stealth, memristive devices, and advanced sensors. However, conventional approaches for tuning the transition temperature, such as elemental doping or heterostructure engineering, often suffer from complicated processing, impurity phases, and poor device uniformity. Here, we use a dopant-free, high-vacuum annealing (9 × 10−4 Pa, ≈9 × 10−6 mbar) strategy to regulate the intrinsic structural evolution of VO2 films via oxygen-vacancy engineering and to clarify its influence on electrical switching contrast and infrared emissivity modulation. As the annealing temperature increases under low oxygen partial pressure, oxygen vacancies gradually accumulate, converting V4+ to V3+ and driving the films through three distinct structural stages: low-temperature lattice expansion with preserved M1 framework, critical structural collapse at 550 °C, and high-temperature defect rearrangement with local recrystallization. Consequently, the electrical MIT temperature continuously decreases, but the switching ratio collapses at the critical point and only partially recovers after high-temperature reorganization, while the infrared emissivity response transitions from abrupt, phase-transition-dominated switching to a continuous, tunable modulation at elevated temperatures. Notably, the infrared response begins continuous tuning earlier (≈450 °C) than the collapse of electrical MIT, reflecting the different sensitivities of optical and electronic responses to local lattice defects. These results reveal the coupling among oxygen-vacancy evolution, structural stability, electrical contrast, and infrared modulation in compositionally simple VO2 films. Compared with conventional doping, this high-vacuum annealing strategy avoids impurity phases, preserves compositional simplicity, and provides a scalable defect-engineering route to design VO2-based devices with reconfigurable electrical and infrared response modes. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Nanomaterials (2079-4991) is the property of MDPI and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.3390/nano16100575 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 14 StartPage: 575 Subjects: – SubjectFull: Oxygen vacancy Type: general – SubjectFull: Annealing of metals Type: general – SubjectFull: Optical modulation Type: general – SubjectFull: Electrochromic windows Type: general – SubjectFull: Metal-insulator transitions Type: general – SubjectFull: Phase transitions Type: general – SubjectFull: Vanadium dioxide Type: general Titles: – TitleFull: Defect-Engineered VO 2 Films: From Abrupt Phase Transition to Continuous Infrared Modulation via High-Vacuum Annealing. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Liu, Lin – PersonEntity: Name: NameFull: Li, Jinxiao – PersonEntity: Name: NameFull: Wu, Lei – PersonEntity: Name: NameFull: Wu, Xiaoling – PersonEntity: Name: NameFull: Cheng, Guoan – PersonEntity: Name: NameFull: Zheng, Ruiting IsPartOfRelationships: – BibEntity: Dates: – D: 15 M: 05 Text: May2026 Type: published Y: 2026 Identifiers: – Type: issn-print Value: 20794991 Numbering: – Type: volume Value: 16 – Type: issue Value: 10 Titles: – TitleFull: Nanomaterials (2079-4991) Type: main |
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