Scalable and Tunable Diamond Nanostructuring Process for Nanoscale NMR Applications

Nanostructuring of a bulk material is used to change its mechanical, optical, and electronic properties and to enable many new applications. We present a scalable fabrication technique that enables the creation of densely packed diamond nanopillars for quantum technology applications. The process yields tunable feature sizes without the employment of lithographic techniques. High-aspect-ratio pillars are created through oxygen-plasma etching of diamond with a dewetted palladium film as an etch mask. We demonstrate an iterative renewal of the palladium etch mask, by which the initial mask thickness is not the limiting factor for the etch depth. Following the process, 300-400 million densely packed 100 nm wide and 1 mu m tall diamond pillars were created on a 3 x 3 mm(2) diamond sample. The fabrication technique is tailored specifically to enable applications and research involving quantum coherent defect center spins in diamond, such as nitrogen-vacancy (NV) centers, which are widely used in quantum science and engineering. To demonstrate the compatibility of our technique with quantum sensing, NV centers are created in the nanopillar sidewalls and are used to sense H-1 nuclei in liquid wetting the nanostructured surface. This nanostructuring process is an important element for enabling the wide-scale implementation of NV-driven magnetic resonance imaging or NV-driven NMR.

Automated summary

Nanostructuring of materials is an important technique to modify their properties and enable new applications. This study presents a scalable fabrication technique for creating densely packed diamond nanopillars, which is useful for quantum technology applications. The technique involves oxygen-plasma etching and an etch mask to create high-aspect-ratio pillars. The research demonstrates the compatibility of the technique with quantum sensing using nitrogen-vacancy centers in diamond nanopillar sidewalls.