Perfect alignment and preferential orientation of nitrogen-vacancy centers during chemical vapor deposition diamond growth on (111) surfaces

TLDR

Synthetic diamond production is essential for quantum metrology and information, with the nitrogen‑vacancy center as the primary qubit, but its four crystallographic orientations create undesirable inhomogeneity. The study aims to demonstrate a microwave plasma‑assisted chemical vapor deposition method on (111) substrates that achieves near‑perfect alignment of NV centers. The method employs MPCVD growth on (111)-oriented substrates, producing NV centers aligned along a single crystallographic direction. The technique yields 94 ± 2 % alignment, with 74 ± 4 % of NVs formed by nitrogen incorporation followed by vacancy creation, resulting in highly homogeneous NV ensembles that benefit quantum applications.

Abstract

Synthetic diamond production is key to the development of quantum metrology and quantum information applications of diamond. The major quantum sensor and qubit candidate in diamond is the nitrogen-vacancy (NV) color center. This lattice defect comes in four different crystallographic orientations leading to an intrinsic inhomogeneity among NV centers that is undesirable in some applications. Here, we report a microwave plasma-assisted chemical vapor decomposition (MPCVD) diamond growth technique on (111)-oriented substrates that yields perfect alignment ($94\pm2%$) of as-grown NV centers along a single crystallographic direction. In addition, clear evidence is found that the majority ($74\pm4%$) of the aligned NV centers were formed by the nitrogen being first included in the (111) growth surface and then followed by the formation of a neighboring vacancy on top. The achieved homogeneity of the grown NV centers will tremendously benefit quantum information and metrology applications.