Spectrally-Resolved Photodynamics of Individual Emitters in Large-Area Monolayers of Hexagonal-Boron Nitride

TL;DR

This study uses advanced microscopy to analyze the photodynamics of individual emitters in large-area hexagonal boron nitride monolayers, revealing homogeneous emitter types and surface effects on emission properties.

Contribution

It demonstrates the application of spectrally-resolved super-resolution microscopy to characterize single emitters in CVD-grown h-BN, highlighting the influence of surface interactions on photodynamics.

Findings

Predominantly one type of emissive state in h-BN monolayers.

Inhomogeneous broadening of emitter linewidths observed.

Power law dependence in fluorescence intermittency similar to quantum dots.

Abstract

Hexagonal boron nitride (h-BN) is a 2D, wide band-gap semiconductor that has recently been shown to display bright room-temperature emission in the visible region, sparking immense interest in the material for use in quantum applications. In this work, we study highly crystalline, single atomic layers of chemical vapour deposition (CVD)-grown hexagonal boron nitride and find predominantly one type of emissive state. Using a multidimensional super-resolution fluorescence microscopy technique we simultaneously measure spatial position, intensity and spectral properties of the emitters, as they are exposed to continuous wave illumination over minutes. As well as low emitter heterogeneity, we observe inhomogeneous broadening of emitter line-widths and power law dependency in fluorescence intermittency, this is in striking similarity to previous work on quantum dots. These results show that high control over h-BN growth and treatment can produce a narrow distribution of emitter type, and that surface interactions heavily influence the photodynamics. Furthermore, we highlight the utility of spectrally-resolved wide-field microscopy in the study of optically-active excitons in atomically thin two-dimensional materials.