Title

Electrodeposited Epitaxial Cu(100) on Si(100) and Lift-Off of Single Crystal-Like Cu(100) Foils

Abstract

A two-step potential electrodeposition technique is described which gives epitaxial films of Cu(100) on n-Si(100). Nucleation of epitaxial seeds occurs at -1.5 VAg/AgCl, whereas the film is grown at -0.5 VAg/AgCl. Cu deposition occurs with a Faradaic efficiency of 82.0% as determined spectrophotometrically. Epitaxy is achieved through a 45° in-plane rotation of Cu with respect to Si, which is shown by X-ray analysis. The 45° rotation reduces the lattice mismatch from -33.43% for an unrotated film to -5.86% for a 45° rotated film. Mosaicity, as determined via X-ray rocking curves, decreases with increasing thickness, going from a full width at half maximum of 3.99° for a 30 nm thick film to 1.67° for a 160 nm thick film. This translates to an increasing quality of epitaxy with increasing thickness. High resolution transmission electron microscopy imaging shows an amorphous SiOx interlayer between Cu and Si. Etching of SiOx with 5% HF allows epitaxial lift-off of the copper film, giving single crystal-like Cu(100) foils. Cu(100) films and single crystal-like foils have potential to be used as catalysts for CO2 reduction, substrates for technologically important materials like spintronic multilayer magnetic stacks and high temperature superconductors, and as active surfaces toward galvanic replacement by platinum group elements. Additionally, the foils could be used as single crystal-like substrates for flexible electronics.

Department(s)

Chemistry

Comments

This work was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering, under grant no. DE-FG02-08ER46518.

Keywords and Phrases

copper; electrodeposition; epitaxy; foil; silicon; single-crystal

International Standard Serial Number (ISSN)

1944-8244; 1944-8252

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2018 American Chemical Society (ACS), All rights reserved.

Publication Date

01 Nov 2018

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