Atomically flat diamond (100) surface formation by anisotropic etching of solid-solution reaction of carbon into nickel

•Diamond (100) surface morphology etched by a solid-solution reaction of C into Ni at 900 °C in Ar was investigated.•The shallow defects due to the surface polishing were removed by the etching.•Atomically flat diamond (100) surfaces with step-terrace structures were formed on the 15 min etched regions.

The morphology of diamond (100) surfaces etched by a solid-solution reaction of C into Ni was investigated. The etching was conducted at 900 °C under an Ar atmosphere. Diamond was selectively etched only under the Ni films. Atomically flat diamond (100) surfaces with step-terrace structures were formed on the etched regions. The step height was approximately 0.18 nm, which is equivalent to that of a double monatomic layer of (100) diamond. The step-edge lines were along the < 110 > directions. These results indicate that the diamond etching by the solid-solution reaction of C into Ni was anisotropic.

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