D and D/He plasma interactions with diamond: Surface modification and D retention

Mathew C. Guenette*, Alec Deslandes, Lars Thomsen, Cormac S. Corr, Daniel P. Riley

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    9 Citations (Scopus)

    Abstract

    Chemical vapour deposition (CVD) diamond is of interest as a plasma facing material in magnetically confined nuclear fusion devices. CVD diamond samples were exposed to ion fluences between 1.5 × 1022ions m- 2and 1 × 1024ions m- 2in D, D/He and He plasmas. A significant surface coverage of 10 nm-100 nm sized hemispherical and conical surface features resulted from chemical erosion and subsequent redeposition on samples exposed to ≤1023ions m- 2when exposed to D containing plasmas. Near edge X-ray absorption fine structure (NEXAFS) spectra showed strong diamond features following plasma exposure, indicating that the diamond crystal structure on the surface was largely retained. A small increase in the sp2fraction (from 1.2% to 4-7%), was observed suggesting some amorphous carbon formation. Elastic recoil detection analysis (ERDA) revealed that D retention saturates at ~ 5.4% averaged over the depth resolution of 20 nm from the surface, for an ion fluence of ~ 1023ions m- 2. The addition of He to the plasma resulted in a slower uptake of D, which was attributed to He ion induced desorption of D.

    Original languageEnglish
    Pages (from-to)103-110
    Number of pages8
    JournalDiamond and Related Materials
    Volume49
    DOIs
    Publication statusPublished - Oct 2014

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