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Nanomechanical and microtribological properties of yttrium thin films for photocathode engineering

Authors :
Alessio Perrone
Esteban Broitman
A. Lorusso
V. Karoutsos
F. Gontad
Nikolaos A. Vainos
Broitman, E.
Lorusso, A.
Perrone, A.
Karoutsos, V.
Vainos, N. A.
Gontad, F.
Source :
Journal of Vacuum Science & Technology A. 37:031507
Publication Year :
2019
Publisher :
American Vacuum Society, 2019.

Abstract

The authors study the nanomechanical and microtribological properties of yttrium (Y) thin films deposited by pulsed laser deposition on Cu polycrystalline substrates. Nanoindentation tests reveal that such films have a high hardness of H = 2.3 GPa and a reduced elastic modulus of 71.7 GPa with respect to the Cu substrates. The friction coefficient between a diamond tip and the Y film reaches a steady state value of μ ∼ 0.34, lower than that for the Cu (μ ∼ 0.38). Moreover, nanoscratch experiments show that Y films are more scratch-resistant than the Cu substrates, probably due to their greater hardness, higher elastic recovery, and lower friction coefficient. Their results confirm that the mechanical and tribological properties of the Y films are suitable for designing and fabricating scratch-resistant hybrid photocathodes and can reduce instabilities and unwanted discharges in the cavity of the radio-frequency gun. Furthermore, the low surface roughness and the low work function of the material are important characteristics for a photocathode based on the Y thin film for the production of high-brightness electron beams.

Details

ISSN :
15208559 and 07342101
Volume :
37
Database :
OpenAIRE
Journal :
Journal of Vacuum Science & Technology A
Accession number :
edsair.doi.dedup.....86ddc3b36f329cdab2e5065d243e471d
Full Text :
https://doi.org/10.1116/1.5088106