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Anisotropic expansion and amorphization of Ga2O3 irradiated with 946MeV Au ions

Tracy, Cameron L. and Lang, Maik and Severin, Daniel and Bender, Markus and Trautmann, Christina and Ewing, Rodney C. (2016):
Anisotropic expansion and amorphization of Ga2O3 irradiated with 946MeV Au ions.
In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, Elsevier Science Publishing, pp. 40-44, 374, ISSN 0168583X,
[Online-Edition: http://dx.doi.org/10.1016/j.nimb.2015.08.059],
[Article]

Abstract

The structural response of β-Ga2O3 to irradiation-induced electronic excitation was investigated. A polycrystalline pellet of this material was irradiated with 946 MeV Au ions and the resulting structural modifications were characterized using in situ X-ray diffraction analysis at various ion fluences, up to 1 × 1013 cm−2. Amorphization was induced, with the accumulation of the amorphous phase following a single-impact mechanism in which each ion produces an amorphous ion track along its path. Concurrent with this phase transformation, an increase in the unit cell volume of the material was observed and quantified using Rietveld refinement. This unit cell expansion increased as a function of ion fluence before saturating at 1.8%. This effect is attributed to the generation of defects in an ion track shell region surrounding the amorphous track cores. The unit cell parameter increase was highly anisotropic, with no observed expansion in the [0 1 0] direction. This may be due to the structure of β-Ga2O3, which exhibits empty channels of connected interstitial sites oriented in this direction.

Item Type: Article
Erschienen: 2016
Creators: Tracy, Cameron L. and Lang, Maik and Severin, Daniel and Bender, Markus and Trautmann, Christina and Ewing, Rodney C.
Title: Anisotropic expansion and amorphization of Ga2O3 irradiated with 946MeV Au ions
Language: English
Abstract:

The structural response of β-Ga2O3 to irradiation-induced electronic excitation was investigated. A polycrystalline pellet of this material was irradiated with 946 MeV Au ions and the resulting structural modifications were characterized using in situ X-ray diffraction analysis at various ion fluences, up to 1 × 1013 cm−2. Amorphization was induced, with the accumulation of the amorphous phase following a single-impact mechanism in which each ion produces an amorphous ion track along its path. Concurrent with this phase transformation, an increase in the unit cell volume of the material was observed and quantified using Rietveld refinement. This unit cell expansion increased as a function of ion fluence before saturating at 1.8%. This effect is attributed to the generation of defects in an ion track shell region surrounding the amorphous track cores. The unit cell parameter increase was highly anisotropic, with no observed expansion in the [0 1 0] direction. This may be due to the structure of β-Ga2O3, which exhibits empty channels of connected interstitial sites oriented in this direction.

Journal or Publication Title: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms
Volume: 374
Publisher: Elsevier Science Publishing
Uncontrolled Keywords: Swift heavy ions, Ion irradiation, X-ray diffraction, Amorphization, Unit cell parameters
Divisions: 11 Department of Materials and Earth Sciences > Material Science > Ion-Beam-Modified Materials
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences
Date Deposited: 15 Jun 2016 07:50
Official URL: http://dx.doi.org/10.1016/j.nimb.2015.08.059
Additional Information:

This article belongs to a special issue: Basic Research on Ionic-Covalent Materials

Identification Number: doi:10.1016/j.nimb.2015.08.059
Funders: This work was supported by the Energy Frontier Research Center Materials Science of Actinides funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences (DE-SC0001089)., C.L.T. acknowledges support from the National Science Foundation Graduate Research Fellowship Program under Grant Number DGE-1256260.
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