Localization of narrowband single photon emitters in nanodiamonds

TL;DR

This study reveals that narrowband single photon emitters in nanodiamonds are localized at extended defects like twin boundaries, and removing these defects eliminates the emission, advancing quantum device fabrication.

Contribution

It demonstrates that extended morphological defects are the origin of narrowband emitters in nanodiamonds and shows defect removal eliminates emission, providing insight into emitter control.

Findings

Emitters are localized at defects such as twin boundaries.

Removing defects via electron beam etching eliminates narrowband emission.

Defects are critical for the presence of single photon emitters.

Abstract

Diamond nanocrystals that host room temperature narrowband single photon emitters are highly sought after for applications in nanophotonics and bio-imaging. However, current understanding of the origin of these emitters is extremely limited. In this work we demonstrate that the narrowband emitters are point defects localized at extended morphological defects in individual nanodiamonds. In particular, we show that nanocrystals with defects such as twin boundaries and secondary nucleation sites exhibit narrowband emission that is absent from pristine individual nanocrystals grown under the same conditions. Critically, we prove that the narrowband emission lines vanish when extended defects are removed deterministically using highly localized electron beam induced etching. Our results enhance the current understanding of single photon emitters in diamond, and are directly relevant to fabrication of novel quantum optics devices and sensors.