Detection of single W-centers in silicon

TL;DR

This paper reports the first detection and detailed analysis of single intrinsic W-centers in silicon, revealing their quantum emission properties and microscopic structure, with implications for quantum photonics.

Contribution

It demonstrates the detection of single intrinsic W-centers in silicon and uncovers their photophysical and structural characteristics, advancing quantum defect research in silicon.

Findings

Single-photon emission from W-centers was observed.

W-centers exhibit a zero-phonon line at 1.218 μm.

Coulomb interactions enable excitonic recombination below the bandgap.

Abstract

Controlling the quantum properties of individual fluorescent defects in silicon is a key challenge towards advanced quantum photonic devices prone to scalability. Research efforts have so far focused on extrinsic defects based on impurities incorporated inside the silicon lattice. Here we demonstrate the detection of single intrinsic defects in silicon, which are linked to a tri-interstitial complex called W-center, with a zero-phonon line at 1.218${\mu}$m. Investigating their single-photon emission properties reveals new information about this common radiation damage center, such as its dipolar orientation and its photophysics. We also identify its microscopic structure and show that although this defect does not feature electronic states in the bandgap, Coulomb interactions lead to excitonic radiative recombination below the silicon bandgap. These results could set the stage for numerous quantum perspectives based on intrinsic luminescent defects in silicon, such as quantum integrated photonics, quantum communications and quantum sensing.