Kobayashi, T.; Nishiyama, F.; Takahiro, K. Chromatic Change in Copper Oxide Layers Irradiated with Low Energy Ions. Quantum Beam Sci.2021, 5, 7.
Kobayashi, T.; Nishiyama, F.; Takahiro, K. Chromatic Change in Copper Oxide Layers Irradiated with Low Energy Ions. Quantum Beam Sci. 2021, 5, 7.
The color of a thin copper oxide layer formed on a copper plate was transformed from reddish-brown into blue-purple by irradiation with 5 keV Ar+ ions to a fluence as low as 1 1015 Ar+ cm–2. In the unirradiated copper oxide layer, the copper valence state of Cu2+ as well as Cu+ and/or Cu0 was included as indicated by the presence of a shake-up satellite line in a photoemission spectrum. While for the irradiated one, the satellite line decreased in intensity, indicating that irradiation resulted in the reduction from Cu2+ to Cu+ and/or Cu0. Furthermore, nuclear reaction analysis using a 16O(d, p)17O reaction with 0.85 MeV deuterons revealed a significant loss of oxygen (51015 O atoms cm–2) in the irradiated layer. Thus, the chromatic change observed in the present work originated in the irradiation-induced reduction of a copper oxide.
ion beam; copper oxide; chromatic change; photoemission spectrum; beam viewer
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