Temperature dependent creation of nitrogen-vacancy centers in CVD diamond layers

TL;DR

This study demonstrates that temperature control during plasma-assisted chemical vapor deposition enables precise creation of nitrogen-vacancy centers in diamond layers, maintaining high spin coherence for advanced magnetometry.

Contribution

It introduces a method to tune NV- center creation via temperature variations during growth, allowing complex stacking and high-density doping without changing gas composition.

Findings

Temperature variations effectively control NV- creation efficiency.

NV- centers exhibit spin coherence comparable to ultra-pure bulk crystals.

Thin layers with high NV- density can be grown without compromising quality.

Abstract

In this work, we explore the ability of plasma assisted chemical vapor deposition (PACVD) operating under high power densities to produce thin high-quality diamond layers with a controlled doping with negatively-charged nitrogen-vacancy (NV-) centers. This luminescent defect possesses specific physical characteristics that make it suitable as an addressable solid-state electron spin for measuring magnetic fields with unprecedented sensitivity. To this aim, a relatively large number of NV- centers (> 10^12 cm^-3) should ideally be located in a thin diamond layer (a few tens of nm) close to the surface which is particularly challenging to achieve with the PACVD technique. Here we show that intentional temperature variations can be exploited to tune NV- creation efficiency during growth, allowing engineering complex stacking structures with a variable doping. Because such a temperature variation can be performed quickly and without any change of the gas phase composition, thin layers can be grown. Measurements show that despite the temperature variations, the luminescent centers incorporated using this technique exhibit spin coherence properties similar to those reached in ultra-pure bulk crystals, which suggests that they could be successfully employed in magnetometry applications.