Oxygen plasma cleaning of copper for photocathode applications: A MEIS and XPS study

T. C.Q. Noakes, R. Valizadeh, A. N. Hannah, L. B. Jones, B. L. Militsyn, S. Mistry, M. D. Cropper, A. Rossall, J. A. Van den Berg

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

MEIS and XPS studies have been conducted for a range of oxygen plasma treated copper samples (and one treated with Ar plasma), as part of a study of the preparation of photocathode surfaces. This procedure was seen to remove hydrocarbon contamination, but left an oxide film whose thickness depended on the treatment conditions used. The film thickness was seen to increase with longer treatment time and higher RF power levels with behaviour characteristic of a diffusion limited process. Annealing led to a removal of the oxide layer by diffusion of oxygen into the bulk of the samples. This indicates that where the oxide layer is sufficiently thin, it should be possible to produce a surface with low enough oxygen content to have adequate conductivity and high enough surface escape probability to allow photoemission at UV wavelengths. Ar plasma treatment was seen to result in a very thin oxide film which could satisfy these requirements and thus might be preferable. Data from single crystal copper samples showed similar total oxygen content for all the surfaces analysed.

Original languageEnglish
Article number111424
Number of pages8
JournalVacuum
Volume205
Early online date15 Sep 2022
DOIs
Publication statusPublished - 1 Nov 2022

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