In situ atomic-resolution study of transformations in double polymorph γ/β-Ga2O3 structures

García-Fernández, J.; Kjeldby, S. B.; Zeng, L. J.; Azarov, A.; Pokle, A.; Nguyen, P. D.; Olsson, E.; Vines, L.; Kuznetsov, A.; Prytz, Ø.

doi:10.1039/d3ma01011b

Cited by 2 publications

(1 citation statement)

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“…In our case, the Yb-O clustering can also be expected [40]. Furthermore, the newest works suggest that the radiationinduced γphase is a disordered version of the β-Ga2O3, where Ga ions of β-Ga2O3-lattice are moved towards interstitial positions [41,42]. Hance, the radiation-induced γphase transition makes a lot of free vacancies, which become mobile during the annealing and could agglomerate.…”

Section: Resultssupporting

confidence: 49%

Anisotropy of radiation-induced defects in Yb-implanted β-Ga2O3

Ratajczak,

Sarwar,

Kalita

et al. 2024

Preprint

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RE-doped β-Ga2O3 seems attractive for future high-power LEDs operating in high irradiation environments. In this work, we pay special attention to the issue of radiation-induced defect anisotropy in β-Ga2O3, which is crucial for device manufacturing. Using the RBS/c technique, we have carefully studied the structural changes caused by implantation and post-implantation annealing in two of the most commonly used crystallographic orientations of β-Ga2O3, namely the (-201) and (010). The analysis was supported by advanced computer simulations using the McChasy code. Our studies reveal a strong dependence of the structural damage induced by Yb-ion implantation on the crystal orientation, with a significantly higher level of extended defects observed in the (-201) direction than for the (010). In contrast, the concentration and behavior of simple defects seem similar for both oriented crystals, although their evolution suggests the coexistence of two different types of defects in the implanted zone with their different sensitivity to both, radiation and annealing. It has also been found that Yb ions mostly occupy the interstitial positions in β-Ga2O3 crystals that remain unchanged after annealing. The location is independent of the crystal orientations. We believe that these studies noticeably extend the knowledge of the radiation-induced defect structure, because they dispel doubts about the differences in the damage level depending on crystal orientation, and are important for further practical applications.

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Section: Resultssupporting

confidence: 49%

Anisotropy of radiation-induced defects in Yb-implanted β-Ga2O3

Ratajczak,

Sarwar,

Kalita

et al. 2024

Preprint

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Optical Activity and Phase Transformations in γ/β Ga₂O₃ Bilayers Under Annealing

Azarov,

Galeckas,

Cora

et al. 2024

Advanced Optical Materials

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Gallium oxide (Ga2O3) can be crystallized in several polymorphs exhibiting different physical properties. In this work, polymorphic structures consisting of the cubic defective spinel (γ) film on the top of the monoclinic (β) substrate are fabricated by disorder‐induced ordering, known to be a practical way to stack these polymorphs together. Such bilayer structures are annealed to investigate optical properties and phase transformations. Specifically, photoluminescence and diffuse reflectance spectroscopy are combined with transmission electron microscopy, Rutherford backscattering/channeling spectrometry and X‐ray diffraction to monitor the evolutions. As a result, a two‐stage annealing kinetics is observed in γ/β Ga2O3 bilayers associated with the epitaxial γ‐to‐β regrowth at the interface at temperatures below 700 °C and a non‐planar γ‐to‐β phase transformation starting at higher temperatures. Thus, the present data enhance understanding of the polymorphism in Ga2O3, interconnecting the phase transformation kinetics with the evolution of the optical properties.

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In situ atomic-resolution study of transformations in double polymorph γ/β-Ga₂O₃ structures

Abstract: Disorder induced formation of metastable Ga2O3 polymorphs as well as their recovery to the stable state upon anneals attract attention both because of the fundamental novelty and rapidly increasing interest...

Cited by 2 publications

References 42 publications

Anisotropy of radiation-induced defects in Yb-implanted β-Ga2O3

Anisotropy of radiation-induced defects in Yb-implanted β-Ga2O3

Optical Activity and Phase Transformations in γ/β Ga₂O₃ Bilayers Under Annealing

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In situ atomic-resolution study of transformations in double polymorph γ/β-Ga2O3 structures

Abstract: Disorder induced formation of metastable Ga2O3 polymorphs as well as their recovery to the stable state upon anneals attract attention both because of the fundamental novelty and rapidly increasing interest...

Cited by 2 publications

References 42 publications

Anisotropy of radiation-induced defects in Yb-implanted β-Ga2O3

Anisotropy of radiation-induced defects in Yb-implanted β-Ga2O3

Optical Activity and Phase Transformations in γ/β Ga2O3 Bilayers Under Annealing

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Product

Resources

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In situ atomic-resolution study of transformations in double polymorph γ/β-Ga₂O₃ structures

Optical Activity and Phase Transformations in γ/β Ga₂O₃ Bilayers Under Annealing