Production of oriented nitrogen-vacancy color centers in synthetic diamond

TL;DR

This study demonstrates that in CVD-grown diamond, NV- centers are preferentially oriented along specific directions, with a small fraction of nitrogen forming NV centers, which could enhance magnetometry sensitivity.

Contribution

It reveals the preferential orientation of NV- centers in CVD diamond and shows that NV centers grow as units rather than by migration, improving understanding for quantum applications.

Findings

Less than 0.5% nitrogen forms NV centers.

NV- centers are preferentially oriented along two directions.

Reducing NV orientations enhances magnetic resonance contrast.

Abstract

The negatively charged nitrogen-vacancy (NV-) center in diamond is an attractive candidate for applications that range from magnetometry to quantum information processing. Here we show that only a fraction of the nitrogen (typically < 0.5 %) incorporated during homoepitaxial diamond growth by Chemical Vapor Deposition (CVD) is in the form of undecorated NV- centers. Furthermore, studies on CVD diamond grown on (110) oriented substrates show a near 100% preferential orientation of NV- centers along only the [111] and [-1-11] directions, rather than the four possible orientations. The results indicate that NV centers grow in as units, as the diamond is deposited, rather than by migration and association of their components. The NV unit of the NVH- is similarly preferentially oriented, but it is not possible to determine whether this defect was formed by H capture at a preferentially aligned NV center or as a complete unit. Reducing the number of NV orientations from 4 orientations to 2 orientations should lead to increased optically-detected magnetic resonance contrast and thus improved magnetic sensitivity in ensemble-based magnetometry.