Highly intensive emission of the NV− centers in synthetic HPHT microdiamonds at low nitrogen doping

K V Bogdanov,A V Baranov,E V Ushakova,M A Baranov,M V Zhukovskaya,V Yu Osipov,A Rampersaud,K Takai

doi:10.1063/1.5045535

Abstract

Synthetic high-pressure high-temperature (HPHT) microdiamonds demonstrate strong resonant-like enhancement of the NV− photoluminescence (PL) at unexpectedly low concentration of the substitutional nitrogen atoms (NS) of 90 ppm, which is significantly smaller than the ∼250 ppm characteristic for conventional HPHT synthesis. The EPR, Raman, and luminescent spectroscopies, including time-resolved PL, provide evidence that this is due to competition between the increase in PL with increasing concentration of the NV− centers and nonradiative deactivation of these centers by defects induced by the NS in the diamond crystal lattice. It is suggested that the intensity of the NV− center emission can be optimized by the appropriate choice of nitrogen doping concentration which does not substantially disrupt the diamond crystal lattice.

Highlights

The neutral and negatively charged nitrogen-vacancy (NV) color centers in diamonds (NV0 and NV−, respectively), consisting of a substitutional nitrogen atom (NS) and an adjacent vacancy, possess a bright luminescence of zero-phonon and phonon-assisted lines
The substitutional nitrogen atoms are embedded into diamond lattices during the high-pressure hightemperature (HPHT) synthesis either without any nitrogen dopant by infiltration from atmospheric air with a concentration of about 150-250 ppm or by using inorganic nitrogen-containing additives,[1] while the vacancies are usually created by irradiation of the diamonds with high energy electrons (2–10 MeV) with fluence up to 1020 e−/cm2.2–5 A subsequent thermal annealing of the diamonds provides greater homogeneity of the vacancy distribution and increased probability of NV center formation
The nitrogen atoms (NS) and NV− concentrations were determined by the analysis of Electron Paramagnetic Resonance (EPR) spectra of the samples, while the structural quality of the diamond microcrystals and the presence of the nonradiative recombination were determined by Raman spectroscopy and the NV− PL intensity and decay measurements

Summary

Introduction

The neutral and negatively charged nitrogen-vacancy (NV) color centers in diamonds (NV0 and NV−, respectively), consisting of a substitutional nitrogen atom (NS) and an adjacent vacancy, possess a bright luminescence of zero-phonon and phonon-assisted lines. The NS and NV− concentrations were determined by the analysis of Electron Paramagnetic Resonance (EPR) spectra of the samples, while the structural quality of the diamond microcrystals and the presence of the nonradiative recombination were determined by Raman spectroscopy and the NV− PL intensity and decay measurements.

Results

Conclusion