Robust Aluminum Nitride Passivation of Silicon Carbide with Near-Surface Quantum Emitters for Quantum Computing and Sensing Applications

TL;DR

This study demonstrates that aluminum nitride passivation effectively stabilizes near-surface quantum emitters in silicon carbide, enhancing their optical properties for quantum computing and sensing applications.

Contribution

First principles calculations show AlN passivation removes surface states and restores optical properties of SiC quantum emitters, offering a stable surface treatment.

Findings

AlN passivation removes surface states from SiC.

Restores optical properties of silicon vacancy defects.

Identifies a new defect at the SiC-AlN interface.

Abstract

Silicon carbide (SiC) hosts a number of point defects that are being explored as single-photon emitters for quantum applications. Unfortunately, these quantum emitters lose their photostability when placed in proximity to the surface of the host semiconductor. In principle, a uniform passivation of the surface's dangling bonds by simple adsorbates, such as hydrogen or mixed hydrogen/hydroxyl groups, should remove detrimental surface effects. However, the usefulness of atomic and molecular passivation schemes is limited by their lack of long-term chemical and/or thermal stability. In this first principles work, we use aluminum nitride (AlN) to passivate SiC surfaces in a core-shell nanowire model. By using a negatively charged silicon vacancy in SiC as the proof-of-principle quantum emitter, we show that AlN-passivation is effective in removing SiC surface states from the band gap and in restoring the defect's optical properties. We also report the existence of a silicon vacancy-based defect at the SiC-AlN interface, which displays distinct spin and optical properties as compared to the other well-studied defects in SiC.