Fabrication and deterministic transfer of high quality quantum emitter in hexagonal boron nitride

TL;DR

This paper presents a reliable method for fabricating and transferring high-quality quantum emitters in hexagonal boron nitride, enhancing their integration into quantum photonic devices with improved optical properties.

Contribution

Developed plasma etching and annealing techniques to create high-quality quantum emitters in hBN and demonstrated a reliable transfer process for scalable quantum photonic integration.

Findings

Defects with narrow spectra and high single photon purity were achieved.

Fabrication parameters significantly influence emitter brightness and formation probability.

The transfer process enables integration of quantum emitters onto various substrates.

Abstract

Color centers in solid state crystals have become a frequently used system for single photon generation, advancing the development of integrated photonic devices for quantum optics and quantum communication applications. In particular, defects hosted by two-dimensional (2D) hexagonal boron nitride (hBN) are a promising candidate for next-generation single photon sources, due to its chemical and thermal robustness and high brightness at room temperature. The 2D crystal lattice of hBN allows for a high extraction efficiency and easy integration into photonic circuits. Here we develop plasma etching techniques with subsequent high temperature annealing to reliably create defects. We show how different fabrication parameters influence the defect formation probability and the emitter brightness. A full optical characterization reveals the higher quality of the created quantum emitters, represented by a narrow spectrum, short excited state lifetime and high single photon purity. We also investigated the photostability on short and very long timescales. We utilize a wet chemically-assisted transfer process to reliably transfer the single photon sources onto arbitrary substrates, demonstrating the feasibility for the integration into scalable photonic quantum information processing networks.