Room-temperature Single Photon Emitters in Cubic Boron Nitride Nanocrystals

TL;DR

This paper demonstrates room-temperature single-photon emission from defects in cubic boron nitride nanocrystals, confirming their potential for quantum technologies and nanoscale metrology.

Contribution

It provides the first unambiguous evidence of optically addressable quantum emitters in cubic boron nitride nanocrystals at room temperature.

Findings

Room-temperature single-photon emission observed in cBN nanocrystals.

Spectrally resolved Raman imaging confirms cubic phase of cBN.

Photon antibunching with g^{2} ~ 0.2 indicates quantum emission.

Abstract

Color centers in wide bandgap semiconductors are attracting broad attention as platforms for quantum technologies relying on room-temperature single-photon emission (SPE), and for nanoscale metrology applications building on the centers' response to electric and magnetic fields. Here, we demonstrate room-temperature SPE from defects in cubic boron nitride (cBN) nanocrystals, which we unambiguously assign to the cubic phase using spectrally resolved Raman imaging. These isolated spots show photoluminescence (PL) spectra with zero-phonon lines (ZPLs) within the visible region (496-700 nm) when subject to sub-bandgap laser excitation. Second-order autocorrelation of the emitted photons reveals antibunching with $g^{2}$ ~ 0.2 and a decay constant of 2.75 ns that is further confirmed through fluorescence lifetime measurements. The results presented herein prove the existence of optically addressable isolated quantum emitters originating from defects in cBN, making this material an interesting platform for opto-electronic devices and quantum applications.