Engineering shallow spins in diamond with nitrogen delta-doping

TL;DR

This paper presents a precise nitrogen delta-doping method during diamond growth to create shallow NV centers with long spin coherence times, enabling advanced quantum sensing and hybrid architectures.

Contribution

It introduces a novel in situ nitrogen delta-doping technique for controlled depth placement of NV centers with preserved long coherence times.

Findings

NV centers with 5-100 nm depth have long T2 coherence times.

Long coherence times enable atomic-scale sensing applications.

Shallow NV centers maintain coherence despite proximity to surface.

Abstract

We demonstrate nanometer-precision depth control of nitrogen-vacancy (NV) center creation near the surface of synthetic diamond using an in situ nitrogen delta-doping technique during plasma-enhanced chemical vapor deposition. Despite their proximity to the surface, doped NV centers with depths (d) ranging from 5 - 100 nm display long spin coherence times, T2 > 100 \mus at d = 5 nm and T2 > 600 \mus at d \geq 50 nm. The consistently long spin coherence observed in such shallow NV centers enables applications such as atomic-scale external spin sensing and hybrid quantum architectures.