Preferential Placement of Aligned Nitrogen Vacancy Centers in Chemical Vapor Deposition Overgrown Diamond Microstructures

The usefulness of nitrogen vacancy (NV) centers in diamond is augmented by a low defect and impurity density in the surrounding host material, and applications benefit from the ability to control the position of the NV centers. Herein, a process to create NV centers on single-crystalline diamond microstructures by chemical vapor deposition (CVD) is presented. Pyramidal structures with {111} side facets are formed during the intrinsic overgrowth of dry chemically etched cylindrical pillars on a substrate with {100} surface orientation. A thin nitrogen-doped epitaxial layer is deposited on top of the pyramids resulting in the creation of NV centers exclusively on the {111} pyramid side faces. Optically detected magnetic resonance (ODMR) and spin echo measurements reveal preferential alignment of the NV centers in a single {111} direction and a 𝑇2 time of 55 ms . The 𝑇2 time of the NV centers is limited by the surrounding substitutional nitrogen (P1 center) concentration of [P1] = 5 ppm . A low density of other paramagnetic spin noise is detected by double-electron electron resonance (DEER) measurements.