Purification of single-photon emission from hBN using post-processing treatments

Chi Li,Milos Toth,Noah Mendelson,Zai-Quan Xu,Mehran Kianinia,Igor Aharonovich

doi:10.1515/nanoph-2019-0099

Abstract

Abstract Single-photon emitters (SPEs) in hexagonal boron nitride (hBN) are promising components for on-chip quantum information processing. Recently, large-area hBN films prepared by chemical vapor deposition (CVD) were found to host uniform, high densities of SPEs. However, the purity of these emitters has, to date, been low, hindering their applications in practical devices. In this work, we present two methods for post-growth processing of hBN, which significantly improve SPEs in hBN films that had been transferred from substrates used for CVD. The emitters exhibit high photon purities in excess of 90% and narrow linewidths of ~3 nm at room temperature. Our work lays a foundation for producing high-quality emitters in an ultra-compact two-dimensional material system and paves the way for deployment of hBN SPEs in scalable on-chip photonic and quantum devices.

Highlights

Solid-state single-photon emitters (SPEs) are sought after for a plethora of applications in quantum technologies [1,2,3]
Largearea hexagonal boron nitride (hBN) films prepared by chemical vapor deposition (CVD) were found to host uniform, high densities of SPEs
We present two methods for postgrowth processing of hBN, which significantly improve SPEs in hBN films that had been transferred from substrates used for CVD

Summary

Introduction

Solid-state single-photon emitters (SPEs) are sought after for a plethora of applications in quantum technologies [1,2,3]. Of the above-mentioned techniques, the CVD process is attractive, as it enables growth of large-area hBN films that can host a high density of SPEs [15] Employment of these hBN films in practical devices often requires transfer of the hBN from the substrate used for CVD and subsequent lithographic patterning processes. We present two practical, reliable methods to achieve high purity of SPEs in hBN – namely, high-temperature annealing in air and ultraviolet (UV) ozone processing Both methods are highly effective at improving the optical quality, namely, photon purity and linewidth of the zero phonon line (ZPL), of CVD-grown hBN and yield SPEs with roomtemperature linewidths of ~3 nm and autocorrelation curves with zero-delay-time intensities of ≤0.1. Li et al.: Purification of single-photon emission from hBN using post-processing treatments

Materials and methods

A nnealing and UV ozone treatment

U V ozone treatment

Results and discussions

Conclusions