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High-frequency/high-field electron paramagnetic resonance generalized spectroscopic ellipsometry characterization of Cr3+ in β-Ga2O3

Rindert, Viktor LU orcid ; Galazka, Zbigniew ; Schubert, Mathias LU orcid and Darakchieva, Vanya LU (2025) In Applied Physics Letters 126(8).
Abstract

Electron paramagnetic resonance of Cr3+ ions in β -Ga2O3 is investigated using terahertz spectroscopic ellipsometry under magnetic field sweeping, a technique that enables the polarization resolving capabilities of ellipsometry for magnetic resonance measurements. We employed a single-crystal chromium-doped β -Ga2O3 sample, grown by the Czochralski method, and performed ellipsometry measurements at magnetic field strengths ranging from 2 to 8 T, at frequencies from 82 to 125 and 190 to 230 GHz, and at a temperature of 15 K. Analysis of the frequency-field diagrams derived from all Mueller matrix elements allowed us to differentiate between the effects of electron spin Zeeman... (More)

Electron paramagnetic resonance of Cr3+ ions in β -Ga2O3 is investigated using terahertz spectroscopic ellipsometry under magnetic field sweeping, a technique that enables the polarization resolving capabilities of ellipsometry for magnetic resonance measurements. We employed a single-crystal chromium-doped β -Ga2O3 sample, grown by the Czochralski method, and performed ellipsometry measurements at magnetic field strengths ranging from 2 to 8 T, at frequencies from 82 to 125 and 190 to 230 GHz, and at a temperature of 15 K. Analysis of the frequency-field diagrams derived from all Mueller matrix elements allowed us to differentiate between the effects of electron spin Zeeman splitting and zero-field splitting and to accurately determine the anisotropic Zeeman splitting g-tensor and the zero-field splitting parameters. Our results confirm that Cr3+ ions predominantly substitute into octahedral gallium sites. Line shape analysis of Mueller matrix element spectra using the Bloch-Brillouin model provides the spin volume concentration of Cr3+ sites, showing very good agreement with results from chemical analysis by inductively coupled plasma-optical emission spectroscopy and suggesting minimal occupation of sites with inactive electron paramagnetic resonance. This study enhances our understanding of the magnetic and electronic properties of chromium-doped β -Ga2O3 and demonstrates the effectiveness of high-frequency/high-field electron paramagnetic resonance generalized spectroscopic ellipsometry for characterizing defects in ultrawide-bandgap semiconductors.

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author
; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Applied Physics Letters
volume
126
issue
8
article number
082105
publisher
American Institute of Physics (AIP)
external identifiers
  • scopus:85219106397
ISSN
0003-6951
DOI
10.1063/5.0255802
language
English
LU publication?
yes
additional info
Publisher Copyright: © 2025 Author(s).
id
e5da1bb7-a079-4968-91ad-2f842b87bc74
date added to LUP
2025-03-17 16:08:02
date last changed
2025-10-14 11:29:53
@article{e5da1bb7-a079-4968-91ad-2f842b87bc74,
  abstract     = {{<p>Electron paramagnetic resonance of Cr<sup>3+</sup> ions in β -Ga<sub>2</sub>O<sub>3</sub> is investigated using terahertz spectroscopic ellipsometry under magnetic field sweeping, a technique that enables the polarization resolving capabilities of ellipsometry for magnetic resonance measurements. We employed a single-crystal chromium-doped β -Ga<sub>2</sub>O<sub>3</sub> sample, grown by the Czochralski method, and performed ellipsometry measurements at magnetic field strengths ranging from 2 to 8 T, at frequencies from 82 to 125 and 190 to 230 GHz, and at a temperature of 15 K. Analysis of the frequency-field diagrams derived from all Mueller matrix elements allowed us to differentiate between the effects of electron spin Zeeman splitting and zero-field splitting and to accurately determine the anisotropic Zeeman splitting g-tensor and the zero-field splitting parameters. Our results confirm that Cr<sup>3+</sup> ions predominantly substitute into octahedral gallium sites. Line shape analysis of Mueller matrix element spectra using the Bloch-Brillouin model provides the spin volume concentration of Cr<sup>3+</sup> sites, showing very good agreement with results from chemical analysis by inductively coupled plasma-optical emission spectroscopy and suggesting minimal occupation of sites with inactive electron paramagnetic resonance. This study enhances our understanding of the magnetic and electronic properties of chromium-doped β -Ga<sub>2</sub>O<sub>3</sub> and demonstrates the effectiveness of high-frequency/high-field electron paramagnetic resonance generalized spectroscopic ellipsometry for characterizing defects in ultrawide-bandgap semiconductors.</p>}},
  author       = {{Rindert, Viktor and Galazka, Zbigniew and Schubert, Mathias and Darakchieva, Vanya}},
  issn         = {{0003-6951}},
  language     = {{eng}},
  month        = {{02}},
  number       = {{8}},
  publisher    = {{American Institute of Physics (AIP)}},
  series       = {{Applied Physics Letters}},
  title        = {{High-frequency/high-field electron paramagnetic resonance generalized spectroscopic ellipsometry characterization of Cr<sup>3+</sup> in β-Ga<sub>2</sub>O<sub>3</sub>}},
  url          = {{http://dx.doi.org/10.1063/5.0255802}},
  doi          = {{10.1063/5.0255802}},
  volume       = {{126}},
  year         = {{2025}},
}