Strongly inhomogeneous distribution of spectral properties of silicon-vacancy color centers in nanodiamonds

TL;DR

This study reveals a highly inhomogeneous distribution of spectral properties in silicon-vacancy centers in nanodiamonds, identifying two distinct clusters with different wavelength and linewidth characteristics, influenced by lattice strain and possible modifications.

Contribution

The paper uncovers the inhomogeneous spectral distribution of SiV centers in nanodiamonds and links it to lattice strain and potential modifications, supported by experimental and theoretical analysis.

Findings

Two distinct clusters of SiV centers with different spectral properties.

Lattice strain explains the ZPL shifts in the first cluster.

Different spectroscopic features and blinking behaviors observed between clusters.

Abstract

The silicon-vacancy (SiV) color center in diamond is a solid-state single photon emitter and spin quantum bit suited as a component in quantum devices. Here, we show that the SiV center in nanodiamond exhibits a strongly inhomogeneous distribution with regard to the center wavelengths and linewidths of the zero-phonon-line (ZPL) emission at room temperature. We find that the SiV centers separate in two clusters: one group exhibits ZPLs with center wavelengths within a narrow range of approximatly 730 nm to 742 nm and broad linewidths between 5 nm and 17 nm, whereas the second group comprises a very broad distribution of center wavelengths between 715 nm and 835 nm, but narrow linewidths from below 1 nm up to 4 nm. Supported by ab initio Kohn-Sham density functional theory calculations we show that the ZPL shifts of the first group are consistently explained by strain in the diamond lattice. Further, we suggest, that the second group showing the strongly inhomogeneous distribution of center wavelengths might be comprised of modified SiV centers. Whereas single photon emission is demonstrated for SiV centers of both clusters, we show that emitters from different clusters show different spectroscopic features such as variations of the phonon sideband spectra and different blinking dynamics.