Combinatorial Cu-Ni Alloy Thin-Film Catalysts for Layer Number Control in Chemical Vapor-Deposited Graphene

Sumeer R. Khanna, Michael G. Stanford, Ivan V. Vlassiouk, Philip D. Rack

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

We synthesized a combinatorial library of Cux Ni1−x alloy thin films via co-sputtering from Cu and Ni targets to catalyze graphene chemical vapor deposition. The alloy morphology, composition, and microstructure were characterized via scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDS), and X-ray diffraction (XRD), respectively. Subsequently, the Cux Ni1−x alloy thin films were used to grow graphene in a CH4-Ar-H2 ambient at atmospheric pressure. The underlying rationale is to adjust the Cux Ni1−x composition to control the graphene. Energy dispersive x-ray spectroscopy (EDS) analysis revealed that a continuous gradient of Cux Ni1−x (25 at. % < x < 83 at.%) was initially achieved across the 100 mm diameter substrate (~0.9%/mm composition gradient). The XRD spectra confirmed a solid solution was realized and the face-centered cubic lattice parameter varied from ~3.52 to 3.58 Ȧ, consistent with the measured composition gradi-ent, assuming Vegard’s law. Optical microscopy and Raman analysis of the graphene layers suggest single layer growth occurs with x > 69 at.%, bilayer growth dominates from 48 at.% < x < 69 at.%, and multilayer (≥3) growth occurs for x < 48 at.%, where x is the Cu concentration. Finally, a large area of bi-layer graphene was grown via a Cux Ni1−x catalyst with optimized catalyst composition and growth temperature.

Original languageEnglish
Article number1553
JournalNanomaterials
Volume12
Issue number9
DOIs
StatePublished - May 1 2022

Funding

Funding: This research was conducted at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility. M.G.S. acknowledges support from the U.S. Department of Energy (DOE) under grant No. DE-SC0002136. Acknowledgments: The authors acknowledge support from the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility. The authors acknowledge that the X-ray diffraction was performed at the Institute of Advanced Materials and Manufacturing facility.

Keywords

  • 2D materials
  • Raman spectroscopy
  • alloys
  • catalyst
  • chemical vapor deposition (CVD)
  • combinatorial sputtering
  • graphene
  • thin film

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