Native oxide formation on pentagonal copper nanowires: A TEM study

SURFACE SCIENCE

卷:672

Article

Hajimammadov, Rashad¹  Mohl, Melinda¹  Kordas, Krisztian¹ 

[1] Univ Oulu, Fac Informat Technol & Elect Engn, Microelect Res Unit, POB 4500, FIN-90570 Oulu, Finland

关键词: Copper nanowires;    Penta-twinned crystal;    Room temperature oxidation;    Growth kinetics;    Copper oxides;   

DOI  :  10.1016/j.susc.2018.03.005

来源: Elsevier

【 摘 要 】

Hydrothermally synthesized copper nanowires were allowed to oxidize in air at room temperature and 30% constant humidity for the period of 22 days. The growth of native oxide layer was followed up by high-resolution transmission electron microscopy and diffraction to reveal and understand the kinetics of the oxidation process. Copper oxides appear in the form of differently oriented crystalline phases around the metallic core as a shell-like layer (Cu2O) and as nanoscopic islands (CuO) on the top of that. Time dependent oxide thickness data suggests that oxidation follows the field-assisted growth model at the beginning of the process, as practically immediately an oxide layer of similar to 2.8 nm thickness develops on the surface. However, after this initial rapid growth, the local field attenuates and the classical parabolic diffusion limited growth plays the main role in the oxidation. Because of the single crystal facets on the side surface of penta-twinned Cu nanowires, the oxidation rate in the diffusion limited regime is lower than in polycrystalline films.

【 授权许可】

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