Engineering shallow and deep level defects in κ-Ga2O3 thin films: comparing metal-organic vapour phase epitaxy to molecular beam epitaxy and the effect of annealing treatments
Abstract
Orthorhombic gallium oxide (κ-Ga2O3) is an ultra-wide bandgap semiconductor with great potential in new generation electronics. Its application is hindered at present by the limited physical understanding of the relationship between synthesis and functional properties. This work discusses the effects of growth method (metal-organic vapour phase epitaxy and molecular beam epitaxy) as well as annealing treatments in different atmospheres (O2, H2) on point defects in κ-Ga2O3 layers epitaxially grown on c-plane sapphire. Comprehensive experimental characterization by X-ray diffraction, photo current- as well as photoluminescence excitation spectroscopy, and X-ray photo electron spectroscopy is combined with first principles calculations of the point defects’ formation and complex-dissociation energies. We demonstrate that for κ-Ga2O3 the concentration of shallow and deep level defects can be sensitively controlled through annealing treatments at temperatures (T = 500 °C) well below the thermal stability threshold of this polymorph. In particular, our results suggest that hydrogen-related defects (e.g., H-interstitials, Ga-vacancies—H complexes) play a key role in this process. While we provide direct exemplary implications of our results for the performances of κ-Ga2O3 based photodetectors, these findings are predicted to impact further application fields of κ-Ga2O3, such as high electron mobility transistors or memory devices.
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BibTeX
@article{mazzolini2026engineering,
title = {{Engineering shallow and deep level defects in κ-Ga2O3 thin films: comparing metal-organic vapour phase epitaxy to molecular beam epitaxy and the effect of annealing treatments}},
author = {P. Mazzolini and J.B. Varley and A. Parisini and A. Sacchi and M. Pavesi and A. Bosio and M. Bosi and L. Seravalli and B.M. Janzen and M.N. Marggraf and N. Bernhardt and M.R. Wagner and A. Ardenghi and O. Bierwagen and A. Falkenstein and J. Kler and R.A. de Souza and M. Martin and F. Mezzadri and C. Borelli and R. Fornari},
journal = {Materials Today Physics},
year = {2026},
month = oct,
doi = {10.1016/j.mtphys.2024.101463},
url = {https://hal.science/hal-05795865v1},
note = {CC BY},
}
RIS
TY - JOUR
TI - Engineering shallow and deep level defects in κ-Ga2O3 thin films: comparing metal-organic vapour phase epitaxy to molecular beam epitaxy and the effect of annealing treatments
AU - P. Mazzolini
AU - J.B. Varley
AU - A. Parisini
AU - A. Sacchi
AU - M. Pavesi
AU - A. Bosio
AU - M. Bosi
AU - L. Seravalli
AU - B.M. Janzen
AU - M.N. Marggraf
AU - N. Bernhardt
AU - M.R. Wagner
AU - A. Ardenghi
AU - O. Bierwagen
AU - A. Falkenstein
AU - J. Kler
AU - R.A. de Souza
AU - M. Martin
AU - F. Mezzadri
AU - C. Borelli
AU - R. Fornari
PY - 2026
DA - 2026/10/12
JO - Materials Today Physics
DO - 10.1016/j.mtphys.2024.101463
UR - https://hal.science/hal-05795865v1
AB - Orthorhombic gallium oxide (κ-Ga2O3) is an ultra-wide bandgap semiconductor with great potential in new generation electronics. Its application is hindered at present by the limited physical understanding of the relationship between synthesis and functional properties. This work discusses the effects of growth method (metal-organic vapour phase epitaxy and molecular beam epitaxy) as well as annealing treatments in different atmospheres (O2, H2) on point defects in κ-Ga2O3 layers epitaxially grown on c-plane sapphire. Comprehensive experimental characterization by X-ray diffraction, photo current- as well as photoluminescence excitation spectroscopy, and X-ray photo electron spectroscopy is combined with first principles calculations of the point defects’ formation and complex-dissociation energies. We demonstrate that for κ-Ga2O3 the concentration of shallow and deep level defects can be sensitively controlled through annealing treatments at temperatures (T = 500 °C) well below the thermal stability threshold of this polymorph. In particular, our results suggest that hydrogen-related defects (e.g., H-interstitials, Ga-vacancies—H complexes) play a key role in this process. While we provide direct exemplary implications of our results for the performances of κ-Ga2O3 based photodetectors, these findings are predicted to impact further application fields of κ-Ga2O3, such as high electron mobility transistors or memory devices.
SN - 2542-5293
ER -