Reconfigurable Schottky-barriers in 2D photodiodes via room-temperature Ozone treatment

Yiwen Bian; Minghang Fan; Tianxing Wang; Caixia Guo

doi:10.1088/1674-4926/26030046

J. Semicond. > Just Accepted

ARTICLES

Reconfigurable Schottky-barriers in 2D photodiodes via room-temperature Ozone treatment

Yiwen Bian¹, Minghang Fan³, Tianxing Wang³ and Caixia Guo^2,

+ Author Affiliations

Corresponding author: Caixia Guo, guocaixia@htu.edu.cn

DOI: 10.1088/1674-4926/26030046CSTR: 32376.14.1674-4926.26030046

Abstract: The integration of two-dimensional (2D) semiconductors with mainstream complementary metal-oxide-semiconductor (CMOS) technology is hampered by the limited ability to adjust device performance after fabrication. Here, we present a differential Schottky-barrier tuning strategy to post-customize the optoelectronic performance based on a two-dimensional asymmetric Schottky contact WSe₂ photodiode, eliminating the need for device re-fabrication. A brief, room-temperature ozone exposure (1.5 min) enables in-situ tuning of the rectification ratio across three orders of magnitude (from 10² to 10⁵) and enhances the peak responsivity at 532 nm by 11.2 times. These effects stem from differential modulation of Schottky barrier height (SBH) at the asymmetric contacts. While the SBH at the WSe₂/Au interface is reduced, the SBH at the WSe₂/graphene junction is elevated, a phenomenon unlocked by the combination of oxidation-induced Fermi-level lowering in WSe₂ and interfacial dipole modification. Our method establishes a "device-after-design" paradigm for 2D material engineering, providing a CMOS-compatible and versatile route toward adaptive optoelectronics for applications in wearable sensing and reconfigurable photonic systems.

Key words: post-customization, ozone oxidation, asymmetric Schottky contacts, 2D materials, CMOS-compatible

References

[1]	Shin Y S, Lee K, Kim Y R, et al. Mobility engineering in vertical field effect transistors based on van der Waals heterostructures. Adv Mater, 2018, 30(9): 1704435 doi: 10.1002/adma.201704435
[2]	Zhang Y, Yao Y Y, Sendeku M G, et al. Recent progress in CVD growth of 2D transition metal dichalcogenides and related heterostructures. Adv Mater, 2019, 31(41): 1901694 doi: 10.1002/adma.201901694
[3]	Pudasaini P R, Oyedele A, Zhang C, et al. High-performance multilayer WSe₂ field-effect transistors with carrier type control. Nano Res, 2018, 11(2): 722 doi: 10.1007/s12274-017-1681-5
[4]	Mak K F, Xiao D, Shan J. Light–valley interactions in 2D semiconductors. Nat Photonics, 2018, 12(8): 451 doi: 10.1038/s41566-018-0204-6
[5]	Dai M J, Zhang X R, Wang Q J. 2D materials for photothermoelectric detectors: Mechanisms, materials, and devices. Adv Funct Mater, 2024, 34(21): 2312872 doi: 10.1002/adfm.202312872
[6]	Chen W Y, Li L, Huang T, et al. Extending Schottky–Mott rule to van der Waals heterostructures of 2D Janus materials: Influence of intrinsic dipoles. Appl Phys Lett, 2023, 123(17): 171601 doi: 10.1063/5.0174594
[7]	Nishio K, Shirasawa T, Shimizu K, et al. Tuning the Schottky barrier height at the interfaces of metals and mixed conductors. ACS Appl Mater Interfaces, 2021, 13(13): 15746 doi: 10.1021/acsami.0c18656
[8]	Boehm A, Fonseca J J, Thürmer K, et al. Engineering of nanoscale heterogeneous transition metal dichalcogenide–Au interfaces. Nano Lett, 2023, 23(7): 2792 doi: 10.1021/acs.nanolett.3c00080
[9]	Padilha J E, Fazzio A, da Silva A J R. Van der Waals heterostructure of phosphorene and graphene: Tuning the Schottky barrier and doping by electrostatic gating. Phys Rev Lett, 2015, 114(6): 066803 doi: 10.1103/PhysRevLett.114.066803
[10]	Zhao Z J, Kang J Z, Rakheja S, et al. Control-gate-free reconfigurable transistor based on 2D MoTe₂ with asymmetric gating. Appl Phys Lett, 2024, 124(7): 073506 doi: 10.1063/5.0177275
[11]	Guo Y G, Wang F Q, Wang Q. An all-carbon vdW heterojunction composed of penta-graphene and graphene: Tuning the Schottky barrier by electrostatic gating or nitrogen doping. Appl Phys Lett, 2017, 111(7): 073503 doi: 10.1063/1.4986604
[12]	Xu D, Zhang S N, Chen J S, et al. Design of the synergistic rectifying interfaces in Mott–Schottky catalysts. Chem Rev, 2023, 123(1): 1 doi: 10.1021/acs.chemrev.2c00426
[13]	Chen Y K, Wang X Q, Cui W G, et al. Multiple Schottky contacts motivated via defects to tune the response ability of electromagnetic waves. Adv Funct Mater, 2025, 35(11): 2417215 doi: 10.1002/adfm.202417215
[14]	Zhang Z, Qiu Z J, Liu R, et al. Schottky-barrier height tuning by means of ion implantation into preformed silicide films followed by drive-In anneal. IEEE Electron Device Lett, 2007, 28(7): 565 doi: 10.1109/LED.2007.900295
[15]	Aswini K, Kunapalli C K, Munirathnam K, et al. Tuning barrier height and enhancing electrical properties of MOS heterojunctions using Fe₂O₃ doped MoO₃ nanocomposite interlayer on Ni/Cr/n-GaN for optoelectronic devices. Phys B Condens Matter, 2025, 714: 417422 doi: 10.1016/j.physb.2025.417422
[16]	Kaur D, Dahiya R, Shivani, et al. Interface-induced origin of Schottky-to-Ohmic-to-Schottky conversion in non-conventional contact to β-Ga₂O₃. Appl Phys Lett, 2024, 124(2): 021601 doi: 10.1063/5.0187009
[17]	Zhang G B, Fan X M, Wang Z J, et al. Self-rectifying memristors for beyond-CMOS computing: Mechanisms, materials, and integration prospects. Nano Micro Lett, 2026, 18(1): 188 doi: 10.1007/s40820-025-02035-1
[18]	Fenouillet-Beranger C, Brunet L, Batude P, et al. A review of low temperature process modules leading up to the first (≤500 °C) planar FDSOI CMOS devices for 3-D sequential integration. IEEE Trans Electron Devices, 2021, 68(7): 3142 doi: 10.1109/TED.2021.3084916
[19]	Arora R, Barr A R, Larson D T, et al. Engineering interfacial charge transfer through modulation doping for 2D electronics. Phys Rev Materials, 2025, 9(2): L021601 doi: 10.1103/PhysRevMaterials.9.L021601
[20]	Shinde P A, Mahamiya V, Safarkhani M, et al. Unveiling the nanoarchitectonics of interfacial electronic coupling in atomically thin 2D WO₃/WSe₂ heterostructure for sodium-ion storage in aqueous system. Adv Funct Mater, 2024, 34(41): 2406333 doi: 10.1002/adfm.202406333
[21]	Martín-Sánchez J, Mariscal A, De Luca M, et al. Effects of dielectric stoichiometry on the photoluminescence properties of encapsulated WSe₂ monolayers. Nano Res, 2018, 11(3): 1399 doi: 10.1007/s12274-017-1755-4
[22]	Lu J P, Carvalho A, Chan X K, et al. Atomic healing of defects in transition metal dichalcogenides. Nano Lett, 2015, 15(5): 3524 doi: 10.1021/acs.nanolett.5b00952
[23]	Jiang Y R, Xing W Q, Li H Z, et al. Controllable carrier concentration of two-dimensional TMDs by forming transition-metal suboxide layer for photoelectric devices. Appl Phys Lett, 2022, 121(2): 022101 doi: 10.1063/5.0097392

Fig. 1. (Color online) Theoretical Design for Differential Schottky Barrier Tuning via Oxidation. (a) Calculated band structure evolution from pristine WSe₂ to partially oxidized phases and WO₂ reference. (b) Schematic illustration of the ozone oxidation process on WSe₂ surface. (c) Energy band alignment evolution of WSe₂ upon oxidation. (d) Density of states (DOS) at the pristine Au/WSe₂ and WSe₂/graphene interfaces. (e) DOS at the oxidized Au/WSe₂ and WSe₂/graphene interfaces. (f) Calculated work function of samples with different oxidation degrees.

DownLoad: Full-Size Img PowerPoint

Fig. 2. (Color online) Device Architecture and Characterization. (a) Schematic of the symmetric bottom-contact WSe₂ photodiode with Au and graphene electrodes. (b) Optical microscopy image of the fabricated device. (c) Atom force microscopy image. (d) High-resolution XPS spectra of W 4f, O1S and Se 3d core levels before and after ozone oxidation. (e) Raman spectra evolution as a function of ozone treatment time.

DownLoad: Full-Size Img PowerPoint

Fig. 3. (Color online) Post-Customized Electrical Performances. (a) Dark I–V characteristics, inset: photograph of symmetric device. (b) Rectification ratio evolution. (c) Thermionic-emission fitting for SBH extraction. (d) Transfer characteristics evolution.

DownLoad: Full-Size Img PowerPoint

Fig. 4. (Color online) Post-Customized Optoelectronic Performance. (a) I−V characteristics under dark & 532 nm illumination. (b) Spectral photoresponsivity of different wavelengths at self-powered mode. (c) Self-powered (0 V bias) temporal response and stability.

DownLoad: Full-Size Img PowerPoint

Fig. 5. (Color online) Schematic diagram of energy band evolution upon oxidation. (a) Energy levels of the isolated materials before contact. (b) Upon contact in the pristine state. (c) Energy levels of oxidized state materials before contact. (d) Upon contact in the oxidized state. E_c: conduction band minimum; E_v: valence band maximum; E_f: Fermi level; Φ: work function.

DownLoad: Full-Size Img PowerPoint

[1]	Shin Y S, Lee K, Kim Y R, et al. Mobility engineering in vertical field effect transistors based on van der Waals heterostructures. Adv Mater, 2018, 30(9): 1704435 doi: 10.1002/adma.201704435
[2]	Zhang Y, Yao Y Y, Sendeku M G, et al. Recent progress in CVD growth of 2D transition metal dichalcogenides and related heterostructures. Adv Mater, 2019, 31(41): 1901694 doi: 10.1002/adma.201901694
[3]	Pudasaini P R, Oyedele A, Zhang C, et al. High-performance multilayer WSe₂ field-effect transistors with carrier type control. Nano Res, 2018, 11(2): 722 doi: 10.1007/s12274-017-1681-5
[4]	Mak K F, Xiao D, Shan J. Light–valley interactions in 2D semiconductors. Nat Photonics, 2018, 12(8): 451 doi: 10.1038/s41566-018-0204-6
[5]	Dai M J, Zhang X R, Wang Q J. 2D materials for photothermoelectric detectors: Mechanisms, materials, and devices. Adv Funct Mater, 2024, 34(21): 2312872 doi: 10.1002/adfm.202312872
[6]	Chen W Y, Li L, Huang T, et al. Extending Schottky–Mott rule to van der Waals heterostructures of 2D Janus materials: Influence of intrinsic dipoles. Appl Phys Lett, 2023, 123(17): 171601 doi: 10.1063/5.0174594
[7]	Nishio K, Shirasawa T, Shimizu K, et al. Tuning the Schottky barrier height at the interfaces of metals and mixed conductors. ACS Appl Mater Interfaces, 2021, 13(13): 15746 doi: 10.1021/acsami.0c18656
[8]	Boehm A, Fonseca J J, Thürmer K, et al. Engineering of nanoscale heterogeneous transition metal dichalcogenide–Au interfaces. Nano Lett, 2023, 23(7): 2792 doi: 10.1021/acs.nanolett.3c00080
[9]	Padilha J E, Fazzio A, da Silva A J R. Van der Waals heterostructure of phosphorene and graphene: Tuning the Schottky barrier and doping by electrostatic gating. Phys Rev Lett, 2015, 114(6): 066803 doi: 10.1103/PhysRevLett.114.066803
[10]	Zhao Z J, Kang J Z, Rakheja S, et al. Control-gate-free reconfigurable transistor based on 2D MoTe₂ with asymmetric gating. Appl Phys Lett, 2024, 124(7): 073506 doi: 10.1063/5.0177275
[11]	Guo Y G, Wang F Q, Wang Q. An all-carbon vdW heterojunction composed of penta-graphene and graphene: Tuning the Schottky barrier by electrostatic gating or nitrogen doping. Appl Phys Lett, 2017, 111(7): 073503 doi: 10.1063/1.4986604
[12]	Xu D, Zhang S N, Chen J S, et al. Design of the synergistic rectifying interfaces in Mott–Schottky catalysts. Chem Rev, 2023, 123(1): 1 doi: 10.1021/acs.chemrev.2c00426
[13]	Chen Y K, Wang X Q, Cui W G, et al. Multiple Schottky contacts motivated via defects to tune the response ability of electromagnetic waves. Adv Funct Mater, 2025, 35(11): 2417215 doi: 10.1002/adfm.202417215
[14]	Zhang Z, Qiu Z J, Liu R, et al. Schottky-barrier height tuning by means of ion implantation into preformed silicide films followed by drive-In anneal. IEEE Electron Device Lett, 2007, 28(7): 565 doi: 10.1109/LED.2007.900295
[15]	Aswini K, Kunapalli C K, Munirathnam K, et al. Tuning barrier height and enhancing electrical properties of MOS heterojunctions using Fe₂O₃ doped MoO₃ nanocomposite interlayer on Ni/Cr/n-GaN for optoelectronic devices. Phys B Condens Matter, 2025, 714: 417422 doi: 10.1016/j.physb.2025.417422
[16]	Kaur D, Dahiya R, Shivani, et al. Interface-induced origin of Schottky-to-Ohmic-to-Schottky conversion in non-conventional contact to β-Ga₂O₃. Appl Phys Lett, 2024, 124(2): 021601 doi: 10.1063/5.0187009
[17]	Zhang G B, Fan X M, Wang Z J, et al. Self-rectifying memristors for beyond-CMOS computing: Mechanisms, materials, and integration prospects. Nano Micro Lett, 2026, 18(1): 188 doi: 10.1007/s40820-025-02035-1
[18]	Fenouillet-Beranger C, Brunet L, Batude P, et al. A review of low temperature process modules leading up to the first (≤500 °C) planar FDSOI CMOS devices for 3-D sequential integration. IEEE Trans Electron Devices, 2021, 68(7): 3142 doi: 10.1109/TED.2021.3084916
[19]	Arora R, Barr A R, Larson D T, et al. Engineering interfacial charge transfer through modulation doping for 2D electronics. Phys Rev Materials, 2025, 9(2): L021601 doi: 10.1103/PhysRevMaterials.9.L021601
[20]	Shinde P A, Mahamiya V, Safarkhani M, et al. Unveiling the nanoarchitectonics of interfacial electronic coupling in atomically thin 2D WO₃/WSe₂ heterostructure for sodium-ion storage in aqueous system. Adv Funct Mater, 2024, 34(41): 2406333 doi: 10.1002/adfm.202406333
[21]	Martín-Sánchez J, Mariscal A, De Luca M, et al. Effects of dielectric stoichiometry on the photoluminescence properties of encapsulated WSe₂ monolayers. Nano Res, 2018, 11(3): 1399 doi: 10.1007/s12274-017-1755-4
[22]	Lu J P, Carvalho A, Chan X K, et al. Atomic healing of defects in transition metal dichalcogenides. Nano Lett, 2015, 15(5): 3524 doi: 10.1021/acs.nanolett.5b00952
[23]	Jiang Y R, Xing W Q, Li H Z, et al. Controllable carrier concentration of two-dimensional TMDs by forming transition-metal suboxide layer for photoelectric devices. Appl Phys Lett, 2022, 121(2): 022101 doi: 10.1063/5.0097392

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Received: 28 March 2026 Revised: 26 April 2026 Online: Accepted Manuscript: 21 May 2026

Article Navigation > Journal of Semiconductors > 2026 > Accepted Manuscript

Yiwen Bian, Minghang Fan, Tianxing Wang, Caixia Guo. Reconfigurable Schottky-barriers in 2D photodiodes via room-temperature Ozone treatment[J]. Journal of Semiconductors, 2026, In Press. doi: 10.1088/1674-4926/26030046 ****Y W Bian, M H Fan, T X Wang, and C X Guo, Reconfigurable Schottky-barriers in 2D photodiodes via room-temperature Ozone treatment[J]. J. Semicond., 2026, accepted doi: 10.1088/1674-4926/26030046

Citation:

Yiwen Bian, Minghang Fan, Tianxing Wang, Caixia Guo. Reconfigurable Schottky-barriers in 2D photodiodes via room-temperature Ozone treatment[J]. Journal of Semiconductors, 2026, In Press. doi: 10.1088/1674-4926/26030046 ****

Y W Bian, M H Fan, T X Wang, and C X Guo, Reconfigurable Schottky-barriers in 2D photodiodes via room-temperature Ozone treatment[J]. J. Semicond., 2026, accepted doi: 10.1088/1674-4926/26030046

Citation:

Y W Bian, M H Fan, T X Wang, and C X Guo, Reconfigurable Schottky-barriers in 2D photodiodes via room-temperature Ozone treatment[J]. J. Semicond., 2026, accepted doi: 10.1088/1674-4926/26030046

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Reconfigurable Schottky-barriers in 2D photodiodes via room-temperature Ozone treatment

DOI: 10.1088/1674-4926/26030046

CSTR: 32376.14.1674-4926.26030046

1.
School of International Education, , Henan Normal University, Xinxiang 453007, China
2.
School of Photoelectronical Engineering, Henan Normal University, Xinxiang 453007, China
3.
School of Physics, Henan Normal University, Xinxiang 453007, China

More Information

Yiwen Bian：Bian Yiwen, an undergraduate student of the 2024 batch, is currently studying in the School of International Education at Henan Normal University, majoring in Electrical Engineering and Automation
Caixia Guo was born in Yucheng, Henan, China, in 1979. She received the M.S. degree from Nanjing University of Science and Technology, Nanjing, China, in 2005 and the Ph.D. degree from Henan Normal University, Xinxiang, China, in 2018. She is currently an Associate Professor with Henan Normal University, Xinxiang. Her current research interests include 2D semiconductor materials and devices
Corresponding author: guocaixia@htu.edu.cn
Received Date: 2026-03-28
Revised Date: 2026-04-26

Available Online: 2026-05-21

Abstract

Abstract

The integration of two-dimensional (2D) semiconductors with mainstream complementary metal-oxide-semiconductor (CMOS) technology is hampered by the limited ability to adjust device performance after fabrication. Here, we present a differential Schottky-barrier tuning strategy to post-customize the optoelectronic performance based on a two-dimensional asymmetric Schottky contact WSe₂ photodiode, eliminating the need for device re-fabrication. A brief, room-temperature ozone exposure (1.5 min) enables in-situ tuning of the rectification ratio across three orders of magnitude (from 10² to 10⁵) and enhances the peak responsivity at 532 nm by 11.2 times. These effects stem from differential modulation of Schottky barrier height (SBH) at the asymmetric contacts. While the SBH at the WSe₂/Au interface is reduced, the SBH at the WSe₂/graphene junction is elevated, a phenomenon unlocked by the combination of oxidation-induced Fermi-level lowering in WSe₂ and interfacial dipole modification. Our method establishes a "device-after-design" paradigm for 2D material engineering, providing a CMOS-compatible and versatile route toward adaptive optoelectronics for applications in wearable sensing and reconfigurable photonic systems.
- post-customization,
- ozone oxidation,
- asymmetric Schottky contacts,
- 2D materials,
- CMOS-compatible

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References(23)