Dissertation
Optical Spectroscopy of Dopants and Defects in Gallium Oxide
Washington State University
Doctor of Philosophy (PhD), Washington State University
12/2024
DOI:
https://doi.org/10.7273/000007251
Abstract
This work examines the effects of dopants on single crystals of gallium oxide (β-Ga2O3) through photoluminescence, Fourier transform infrared, ultraviolet and visible spectroscopy, and Hall effect measurements.
Key findings include the observation that Cr3+ photoluminescence is prominent in insulating samples but weak in n-type samples. High-energy electron irradiation of n-type β-
Ga2O3 created gallium vacancies, leading to significant changes in color and conductivity, with a notable suppression of free-carrier absorption and the emergence of Cr3+ emissions.
Further investigation of Cr and Zr co-doped β-Ga2O3 samples revealed that despite a high carrier concentration, and therefore a Fermi level within the conduction band, Cr3+ absorption and emissions were still observable. This suggests that the Cr acceptor level may reside within the conduction band. The Cr3+ PL was quenched compared to that of insulating samples. This quenching is likely due to the free carriers in the conduction band, which introduces additional non-radiative recombination pathways.
Spatially resolved PL and Raman mapping were instrumental in identifying specific defect features, such as bright emitter centers associated with Si-CH compounds. Moreover,
these techniques unveiled optically active precipitates, including ZnO and Cu2O, in doped β-Ga2O3 samples.
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Details
- Title
- Optical Spectroscopy of Dopants and Defects in Gallium Oxide
- Creators
- Cassandra Remple
- Contributors
- Matthew D McCluskey (Chair)John S McCloy (Committee Member)Yi Gu (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- School of Mechanical and Materials Engineering
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Publisher
- Washington State University
- Number of pages
- 244
- Identifiers
- 99901195630801842
- Language
- English
- Resource Type
- Dissertation