Theoretical studies on the stabilization and diffusion behaviors of helium impurities in 6H-SiC by DFT calculations

Autor: Obaid Obaidullah, RuiXuan Zhao, XiangCao Li, ChuBin Wan, TingTing Sui, Xin Ju
Jazyk: angličtina
Rok vydání: 2023
Předmět:
Zdroj: Nuclear Engineering and Technology, Vol 55, Iss 8, Pp 2879-2888 (2023)
Druh dokumentu: article
ISSN: 1738-5733
DOI: 10.1016/j.net.2023.05.015
Popis: In fusion environments, large scales of helium (He) atoms are produced by a radical transformation along with structural damage in structural materials, resulting in material swelling and degradation of physical properties. To understand its irradiation effects, this paper investigates the stability, electronic structure, energetics, charge density distribution, PDOS and TDOS, and diffusion processes of He impurities in 6H-SiC materials. The formation energy indicates that a stable, favorable position for interstitial He is the HR site with the lowest energy of 2.40 eV. In terms of vacancy, the He atom initially prefers to substitute at pre-existing Si vacancy than C vacancy due to lower substitution energy. The minimum energy paths (MEPs) with migration energy barriers are also calculated for He impurity by interstitial and vacancy-mediated diffusion. Based on its calculated energy barriers, the most possible diffusion path includes the exchange of interstitial and vacancy sites with effective migration energies ranging from 0.101 eV to 1.0 eV. Our calculation provides a better understanding of the stabilization and diffusion behaviors of He impurities in 6H-SiC materials.
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