Single-crystal diamond microneedles shaped at growth stage

•Single crystal diamonds were produced by oxidation of CVD (001) textured films.•The diamonds have a geometrically perfect pyramid shape with rectangular base.•Computer simulations of the CVD growth and oxidation were developed and verified.•Variation of the CVD parameters allows one to control the pyramid shape and length.•The developed technique allows mass production of the micro-needle diamonds.

Single-crystal diamond microneedles were extracted from (001) textured polycrystalline films. The films were produced using a plasma enhanced chemical vapor deposition (CVD) from a CH4/H2 gas mixture activated by a direct current discharge. The as-grown textured polycrystalline CVD films consist of pyramid-shaped micrometer size diamond crystallites embedded into a nanodiamond ballas-like material. The less ordered fraction of the CVD film material was removed selectively using thermal oxidation. A dependence of the diamond needle shape on the CVD and the oxidation process parameters was revealed via a computer simulation and experimental studies. Ability for mass production of the diamond microneedles of different shapes was demonstrated. The needles are suitable for various applications from microcutting tools to quantum information processing.

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