Engineering near infrared single photon emitters in ultrapure silicon carbide

TL;DR

This paper demonstrates the controlled creation of near-infrared single photon emitters in ultrapure silicon carbide, with potential applications in quantum computing and sensing, by tuning spin centre density via neutron irradiation.

Contribution

It achieves the first controlled engineering of single spin centres in silicon carbide, enabling stable single photon emission at room temperature.

Findings

Controlled spin centre density over 8 orders of magnitude.

Identification of silicon vacancies as single photon emitters.

Stable single photon emission with no bleaching after extensive excitation.

Abstract

Quantum emitters hosted in crystalline lattices are highly attractive candidates for quantum information processing, secure networks and nanosensing. For many of these applications it is necessary to have control over single emitters with long spin coherence times. Such single quantum systems have been realized using quantum dots, colour centres in diamond, dopants in nanostructures and molecules . More recently, ensemble emitters with spin dephasing times on the order of microseconds and room-temperature optically detectable magnetic resonance have been identified in silicon carbide (SiC), a compound being highly compatible to up-to-date semiconductor device technology. So far however, the engineering of such spin centres in SiC on single-emitter level has remained elusive. Here, we demonstrate the control of spin centre density in ultrapure SiC over 8 orders of magnitude, from below $10^{9}$ to above $10^{16} \,$cm$^{-3}$ using neutron irradiation. For a low irradiation dose, a fully photostable, room-temperature, near infrared (NIR) single photon emitter can clearly be isolated, demonstrating no bleaching even after $10^{14}$ excitation cycles. Based on their spectroscopic fingerprints, these centres are identified as silicon vacancies, which can potentially be used as qubits, spin sensors and maser amplifiers.