Dimensionality effects on the luminescence properties of hBN

TL;DR

This study investigates how the number of layers in hexagonal boron nitride affects its luminescence properties, revealing intrinsic emission features and layer-dependent spectral modifications related to 2D excitons.

Contribution

It provides new insights into the layer-dependent luminescence behavior of hBN and confirms the intrinsic nature of the S series emission across different synthesis methods.

Findings

The S series emission is intrinsic to hBN.

Luminescence spectra change significantly with layer number.

Layer-dependent modifications are linked to 2D exciton effects.

Abstract

Cathodoluminescence (CL) experiments at low temperature have been undertaken on various bulk and exfoliated hexagonal boron nitride (hBN) samples. Different bulk crystals grown from different synthesis methods have been studied. All of them present the same so-called S series in the 5.6--6 eV range, proving its intrinsic character. Luminescence spectra of flakes containing 100 down to 6 layers have been recorded. Strong modifications in the same UV range are observed and discussed within the general framework of 2D exciton properties in lamellar crystals.