Magneto-optical properties of Cr3+in β-Ga2O3

Jan E. Stehr, Mattias Jansson, Detlev M. Hofmann, Jihyun Kim, Stephen J. Pearton, Weimin M. Chen, Irina A. Buyanova

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15 Citations (Scopus)


β-Ga2O3 is a wide bandgap semiconductor that is attractive for various applications, including power electronics and transparent conductive electrodes. Its properties can be strongly affected by transition metal impurities commonly present during the growth such as Cr. In this Letter, we determine the electronic structure of Cr3+ by performing a correlative study of magneto-photoluminescence (magneto-PL) and electron paramagnetic resonance. We unambiguously prove that the so-called R1 and R2 PL lines at around 1.79 eV originate from an internal transition between the first excited state (2E) and the 4A2 ground state of Cr3+. The center is concluded to have monoclinic local symmetry and exhibits a large zero-field splitting (∼147 μeV) of the ground state, which can be directly measured from the fine structure of the R1 transition. Furthermore, g-values of the first excited state are accurately determined as ga = 1.7, gb = 1.5, and gc* = 2.1. Our results advance our understanding of the electronic structure of Cr in β-Ga2O3 and provide a spectroscopic signature of this common residual impurity.

Original languageEnglish
Article number052101
JournalApplied Physics Letters
Issue number5
Publication statusPublished - 2021 Aug 2

Bibliographical note

Funding Information:
We would like to thank Leibniz-Institut fu€r Kristallzu€chtung (Berlin) for providing the β-Ga2O3 bulk crystal sample. Financial support by Linkoping University through the Professor Contracts and the Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU No. 2009 00971) is greatly appreciated. The work at UF was supported by the Interaction of Ionizing Radiation with Matter University Research Alliance (IIRM-URA), sponsored by the Department of the Defense, Defense Threat Reduction Agency under Award No. HDTRA1-20-2-0002 and also by NSF DMR (No. 1856662) (James Edgar).

Publisher Copyright:
© 2021 Author(s).

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)


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