Robust single photon sources based on colour centres in silicon carbide

Purpose and goal:

The project aims at solving problems of charge-state instability of single photon emitters (SPEs) of spin-active photoluminescence centres in silicon carbide (SiC), which emit light near and at telecom wavelengths, such as the Si vacancy, divacancy and vanadium. Our goal is to achieve stable and bright SPEs with narrow optical linewidths and long spin coherence times to meet requirements for quantum repeaters, which are key elements for developing long-distance quantum communications using existing fiber networks.

Expected results and effects:

The charge state of defects will be stabilized by employing p-type materials for reducing electron traps within the bandgap. This approach enables stable charge states for single defects under resonant excitation without requiring a repump laser. Consequently, it minimizes defect ionization and reduces charge fluctuations in the local environment under optical excitation, resulting in narrower optical linewidths.

Our approach has been successfully demonstrated for single divacancies and is also expected to be effective for Si vacancies. Approach and implementation:

During the first three months, we focus on realization of single defects by electron irradiation and ion implantation. The optimization of processes for obtaining optimized defect density will be carried out in parallel. In the last five months, we will concentrate on charge state control and characterization of the optical and spin properties of single defects to establish procedures of material and defect control for achieving stable single emitters.