Spin coherence and depths of single nitrogen-vacancy centers created by ion implantation into diamond via screening masks

TL;DR

This study investigates the creation of near-surface nitrogen-vacancy centers in diamond via ion implantation through screening masks, analyzing their coherence times, depths, and surface effects to improve quantum sensing applications.

Contribution

It demonstrates that ion implantation with screening masks can reliably produce shallow NV centers and characterizes their coherence properties and surface interactions.

Findings

NV centers are predominantly within 10 nm of the surface.

Surface effects significantly influence NV spin coherence times.

Screening masks modify ion distribution, enabling controlled NV depth placement.

Abstract

We characterize single nitrogen-vacancy (NV) centers created by 10-keV N+ ion implantation into diamond via thin SiO$_2$ layers working as screening masks. Despite the relatively high acceleration energy compared with standard ones (< 5 keV) used to create near-surface NV centers, the screening masks modify the distribution of N$^+$ ions to be peaked at the diamond surface [Ito et al., Appl. Phys. Lett. 110, 213105 (2017)]. We examine the relation between coherence times of the NV electronic spins and their depths, demonstrating that a large portion of NV centers are located within 10 nm from the surface, consistent with Monte Carlo simulations. The effect of the surface on the NV spin coherence time is evaluated through noise spectroscopy, surface topography, and X-ray photoelectron spectroscopy.