Effect of oxygen content on p-type electrical conductivity in β-Ga2O3 films

Se-Rim Park; Zeyu Chi; Corinne Sartel; sang-Mo Koo; Matthieu Fregnaux; Yunlin Zheng; Sean Douglas; Lewis Penman; Fabien Massabuau; Tamar Tchelidze; Jean-Michel Chauveau; Ekaterine Chikoidze

doi:10.1016/j.mssp.2025.110003

Effect of oxygen content on p-type electrical conductivity in β-Ga2O3 films

Se-Rim Park
, Zeyu Chi^*
, Corinne Sartel
, sang-Mo Koo
, Matthieu Fregnaux
, Yunlin Zheng
, Sean Douglas
, Lewis Penman
, Fabien Massabuau
, Tamar Tchelidze
, Jean-Michel Chauveau^*
, Ekaterine Chikoidze^*

^*Corresponding author for this work

Physics

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

2 Citations (Scopus)

29 Downloads (Pure)

Abstract

β-Ga2O3 is a promising ultrawide bandgap semiconductor, but achieving reliable p-type conductivity remains a challenge, especially due to the scarcity of high-quality homoepitaxial p-type β-Ga2O3 layers. In this study, we investigate β-Ga2O3 thin films homoepitaxially grown on (-201) Fe doped β-Ga2O3 substrates via metal organic chemical vapor deposition under different oxygen-to-gallium (O/Ga) ratios. We examine the effect of oxygen content on the structural, electrical, and optical properties of thin films. The layer grown under oxygen-rich conditions (O/Ga = 6400) exhibited an enhanced crystallinity of the dominant (-201) orientation as indicated by a low full-width at half maximum (FWHM) of 72 arcsec in the X-ray diffraction rocking curve, a suppressed oxygen vacancy signal in X-ray photoelectron spectroscopy, and a two order of magnitude increase in hole concentration (p = 4.5 × 1015 cm−3 vs. 4.6 × 1013 cm−3 at 570 K), associated with a shallow acceptor level with an activation energy of 0.21 eV, likely due to
V_Ga- - VO++ complex-like defect. In addition, both films exhibit hole mobility μH > 30 cm2/V·s over the measurement temperature range. These findings suggest that oxygen-rich growth conditions enhance both the crystallinity and native hole conductivity of β-Ga2O3, offering a promising route toward achieving controlled p-type behavior in this material.

Original language	English
Article number	110003
Journal	Materials Science in Semiconductor Processing
Volume	200
Early online date	29 Aug 2025
DOIs	https://doi.org/10.1016/j.mssp.2025.110003
Publication status	Published - Dec 2025

Funding

The work in France has been funded by French National Agency of Research (ANR), project “GOPOWER”, CE-50 N0015-01 and MRSEI PHC-Maimonide N50047TD. Dr. E. Chikoidze would acknowledge IRP-CNRS “GALLIA” project giving possibility to cooperate with colleagues from University of Strathclyde. The work has been funded by the Engineering and Physical Sciences Research Council (grants EP/W524670/1, EP/V034995/1) and UK Space Agency's Enabling Technologies Programme UK Space Agency (UKSAG23_0043_ETP4-052). Serim Park acknowledges Fostering Global Talents for Innovative Growth Program through KIAT of the MOTIE (P0017308), the France 2030 programme “ANR-11-IDEX-0003″ via Integrative Institute of Materials from Paris-Saclay University - 2IM@UPSaclay.

Keywords

β-Ga2O3
p-type conductivity
Homoepitaxy
Oxygen content

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10.1016/j.mssp.2025.110003

Park-etal-2025-Effect-of-oxygen-content-on-p-type-electrical-conductivity-in-β-Ga2O3-filmsAccepted author manuscript, 1.13 MBLicence: CC BY 4.0

Cite this

@article{d9f999136dbe4472a926a95c2a83dfc1,

title = "Effect of oxygen content on p-type electrical conductivity in β-Ga2O3 films",

abstract = "β-Ga2O3 is a promising ultrawide bandgap semiconductor, but achieving reliable p-type conductivity remains a challenge, especially due to the scarcity of high-quality homoepitaxial p-type β-Ga2O3 layers. In this study, we investigate β-Ga2O3 thin films homoepitaxially grown on (-201) Fe doped β-Ga2O3 substrates via metal organic chemical vapor deposition under different oxygen-to-gallium (O/Ga) ratios. We examine the effect of oxygen content on the structural, electrical, and optical properties of thin films. The layer grown under oxygen-rich conditions (O/Ga = 6400) exhibited an enhanced crystallinity of the dominant (-201) orientation as indicated by a low full-width at half maximum (FWHM) of 72 arcsec in the X-ray diffraction rocking curve, a suppressed oxygen vacancy signal in X-ray photoelectron spectroscopy, and a two order of magnitude increase in hole concentration (p = 4.5 × 1015 cm−3 vs. 4.6 × 1013 cm−3 at 570 K), associated with a shallow acceptor level with an activation energy of 0.21 eV, likely due to V\_Ga- - VO++ complex-like defect. In addition, both films exhibit hole mobility μH > 30 cm2/V·s over the measurement temperature range. These findings suggest that oxygen-rich growth conditions enhance both the crystallinity and native hole conductivity of β-Ga2O3, offering a promising route toward achieving controlled p-type behavior in this material.",

keywords = "β-Ga2O3, p-type conductivity, Homoepitaxy, Oxygen content",

author = "Se-Rim Park and Zeyu Chi and Corinne Sartel and sang-Mo Koo and Matthieu Fregnaux and Yunlin Zheng and Sean Douglas and Lewis Penman and Fabien Massabuau and Tamar Tchelidze and Jean-Michel Chauveau and Ekaterine Chikoidze",

year = "2025",

month = dec,

doi = "10.1016/j.mssp.2025.110003",

language = "English",

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T1 - Effect of oxygen content on p-type electrical conductivity in β-Ga2O3 films

AU - Park, Se-Rim

AU - Chi, Zeyu

AU - Sartel, Corinne

AU - Koo, sang-Mo

AU - Fregnaux, Matthieu

AU - Zheng, Yunlin

AU - Douglas, Sean

AU - Penman, Lewis

AU - Massabuau, Fabien

AU - Tchelidze, Tamar

AU - Chauveau, Jean-Michel

AU - Chikoidze, Ekaterine

PY - 2025/12

Y1 - 2025/12

N2 - β-Ga2O3 is a promising ultrawide bandgap semiconductor, but achieving reliable p-type conductivity remains a challenge, especially due to the scarcity of high-quality homoepitaxial p-type β-Ga2O3 layers. In this study, we investigate β-Ga2O3 thin films homoepitaxially grown on (-201) Fe doped β-Ga2O3 substrates via metal organic chemical vapor deposition under different oxygen-to-gallium (O/Ga) ratios. We examine the effect of oxygen content on the structural, electrical, and optical properties of thin films. The layer grown under oxygen-rich conditions (O/Ga = 6400) exhibited an enhanced crystallinity of the dominant (-201) orientation as indicated by a low full-width at half maximum (FWHM) of 72 arcsec in the X-ray diffraction rocking curve, a suppressed oxygen vacancy signal in X-ray photoelectron spectroscopy, and a two order of magnitude increase in hole concentration (p = 4.5 × 1015 cm−3 vs. 4.6 × 1013 cm−3 at 570 K), associated with a shallow acceptor level with an activation energy of 0.21 eV, likely due to V_Ga- - VO++ complex-like defect. In addition, both films exhibit hole mobility μH > 30 cm2/V·s over the measurement temperature range. These findings suggest that oxygen-rich growth conditions enhance both the crystallinity and native hole conductivity of β-Ga2O3, offering a promising route toward achieving controlled p-type behavior in this material.

AB - β-Ga2O3 is a promising ultrawide bandgap semiconductor, but achieving reliable p-type conductivity remains a challenge, especially due to the scarcity of high-quality homoepitaxial p-type β-Ga2O3 layers. In this study, we investigate β-Ga2O3 thin films homoepitaxially grown on (-201) Fe doped β-Ga2O3 substrates via metal organic chemical vapor deposition under different oxygen-to-gallium (O/Ga) ratios. We examine the effect of oxygen content on the structural, electrical, and optical properties of thin films. The layer grown under oxygen-rich conditions (O/Ga = 6400) exhibited an enhanced crystallinity of the dominant (-201) orientation as indicated by a low full-width at half maximum (FWHM) of 72 arcsec in the X-ray diffraction rocking curve, a suppressed oxygen vacancy signal in X-ray photoelectron spectroscopy, and a two order of magnitude increase in hole concentration (p = 4.5 × 1015 cm−3 vs. 4.6 × 1013 cm−3 at 570 K), associated with a shallow acceptor level with an activation energy of 0.21 eV, likely due to V_Ga- - VO++ complex-like defect. In addition, both films exhibit hole mobility μH > 30 cm2/V·s over the measurement temperature range. These findings suggest that oxygen-rich growth conditions enhance both the crystallinity and native hole conductivity of β-Ga2O3, offering a promising route toward achieving controlled p-type behavior in this material.

KW - β-Ga2O3

KW - p-type conductivity

KW - Homoepitaxy

KW - Oxygen content

UR - https://doi.org/10.17868/strath.00094012

U2 - 10.1016/j.mssp.2025.110003

DO - 10.1016/j.mssp.2025.110003

M3 - Article

SN - 1873-4081

VL - 200

JO - Materials Science in Semiconductor Processing

JF - Materials Science in Semiconductor Processing

M1 - 110003

ER -

Effect of oxygen content on p-type electrical conductivity in β-Ga2O3 films

Abstract

Funding

Keywords

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DTP 2224 University of Strathclyde | Penman, Lewis

Photoluminescence setup JA2.02A - 224 nm laser (Photon System HeAg 70-224SL)

Tuneable radiation-resilient (AlGa)2O3 UVC photodetectors

EPSRC Capital Core Equipment Award 2020

Cite this

Effect of oxygen content on p-type electrical conductivity in β-Ga2O3 films

Abstract

Funding

Keywords

Access to Document

Other files and links

Fingerprint

Projects

DTP 2224 University of Strathclyde | Penman, Lewis

Photoluminescence setup JA2.02A - 224 nm laser (Photon System HeAg 70-224SL)

Tuneable radiation-resilient (AlGa)2O3 UVC photodetectors

Prizes

EPSRC Capital Core Equipment Award 2020

Cite this