Hydrogen Release and Retention Dynamics of Amorphous Carbon Layers Exposed to a Hydrogen/Helium Plasma
- 1 June 1989
- journal article
- Published by IOP Publishing in Japanese Journal of Applied Physics
- Vol. 28 (6R), 1101-1108
- https://doi.org/10.1143/jjap.28.1101
Abstract
H2 and DH release was measured in a pulsed deuterium discharge over a carbon-thin-film deposited wall. The 300 eV D2 + irradiation induced a large quantity of hydrogen release from carbon layers deposited by a H2+CH4 discharge. On the other hand, a strong pumping effect was observed for carbon layers deposited by a He+CH4 discharge. The pumping effect was attributed to interstitial vacancies in the films. Experimental evidence suggesting molecular formation by direct hydrogen abstraction was found. A dynamic model of hydrogen recycling on carbon layers is proposed. Corresponding calculations yield satisfactory agreement with observations. The pumping effect was always observed after conditioning of the wall with a helium glow discharge. The helium ion bombardment creates many interstitial vacancies after the hydrogen release.Keywords
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