Spin Properties of Very Shallow Nitrogen Vacancy Defects in Diamond

TL;DR

This study characterizes the spin and optical properties of nitrogen-vacancy centers in diamond located within 1-10 nm of the surface, highlighting their stability and spectral features crucial for nanoscale sensing applications.

Contribution

It provides detailed analysis of shallow NV centers' properties, demonstrating their stability and spectral behavior near the surface, which is vital for quantum sensing technologies.

Findings

Stable NV centers observed down to 1 nm depth

Spectral broadening occurs for defects shallower than 2 nm

Surface paramagnetic impurities influence spectral properties

Abstract

We investigate spin and optical properties of individual nitrogen-vacancy centers located within 1-10 nm from the diamond surface. We observe stable defects with a characteristic optically detected magnetic resonance spectrum down to lowest depth. We also find a small, but systematic spectral broadening for defects shallower than about 2 nm. This broadening is consistent with the presence of a surface paramagnetic impurity layer [Tisler et al., ACS Nano 3, 1959 (2009)] largely decoupled by motional averaging. The observation of stable and well-behaved defects very close to the surface is critical for single-spin sensors and devices requiring nanometer proximity to the target.