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Effects of elevated-temperature deposition on the atomic structure of amorphous Ta₂O₅ films

K. Prasai, K. Lee, Bill Baloukas, H. P. Cheng, M. Fazio, Ludvik Martinu, A. Mehta, C. S. Menoni, F. Schiettekatte, R. Shink, B. Shyam, G. Vajente, M. M. Fejer and R. Bassiri

Article (2023)

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Brownian thermal noise as a result of mechanical loss in optical coatings will become the dominant source of noise at the most sensitive frequencies of ground-based gravitational-wave detectors. Experiments found, however, that a candidate material, amorphous Ta2O5, is unable to form an ultrastable glass and, consequently, to yield a film with significantly reduced mechanical loss through elevated-temperature deposition alone. X-ray scattering PDF measurements are carried out on films deposited and subsequently annealed at various temperatures. Inverse atomic modeling is used to analyze the short and medium range features in the atomic structure of these films. Furthermore, in silico deposition simulations of Ta2O5 are carried out at various substrate temperatures and an atomic level analysis of the growth at high temperatures is presented. It is observed that upon elevated-temperature deposition, short range features remain identical, whereas medium range order increases. After annealing, however, both the short and medium range orders of films deposited at different substrate temperatures are nearly identical. A discussion on the surface diffusion and glass transition temperatures indicates that future pursuits of ultrastable low-mechanical-loss films through elevated temperature deposition should focus on materials with a high surface mobility, and/or lower glass transition temperatures in the range of achievable deposition temperatueres.

Uncontrolled Keywords

molecular dynamics; amorphous materials; annealing; vapor deposition; x-ray scattering; atomic structure

Subjects: 1900 Biomedical engineering > 1900 Biomedical engineering
2500 Electrical and electronic engineering > 2500 Electrical and electronic engineering
3100 Physics > 3100 Physics
3100 Physics > 3101 Atomic and molecular studies
Department: Department of Engineering Physics
Funders: NSERC / CRSNG, LSC Center for Coatings Research, National Science Foundation (NSF), Gordon and Betty Moore Foundation (GBMF), Office of Naval Research (ONR), Fonds de recherche du Québec - Nature et technologie (FRQNT), National Research Foundation of Korea (NRF), Fondation canadienne pour l'innovation (FCI)
Grant number: PHY-2011571, PHY-2011706, PHY-2011782, 6793, N000-17-1-2536, ACI-1548562, 2021R1C1C1009248, P2300147
PolyPublie URL: https://publications.polymtl.ca/57310/
Journal Title: APL Materials (vol. 11, no. 12)
Publisher: AIP Publishing
DOI: 10.1063/5.0170100
Official URL: https://doi.org/10.1063/5.0170100
Date Deposited: 29 Jan 2024 14:38
Last Modified: 03 May 2024 20:37
Cite in APA 7: Prasai, K., Lee, K., Baloukas, B., Cheng, H. P., Fazio, M., Martinu, L., Mehta, A., Menoni, C. S., Schiettekatte, F., Shink, R., Shyam, B., Vajente, G., Fejer, M. M., & Bassiri, R. (2023). Effects of elevated-temperature deposition on the atomic structure of amorphous Ta₂O₅ films. APL Materials, 11(12), 121112 (8 pages). https://doi.org/10.1063/5.0170100


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