# Identifying the Origin of Hexagonal Boron Nitride Single Photon Emitters with nano-FTIR

## TL;DR

This paper identifies that single photon emitters in hexagonal boron nitride originate from carbonized organic residues, not the hBN itself, using nano-FTIR.

## Contribution

The study provides direct evidence that hBN single photon emitters come from carbonized organic residues, not the hBN lattice.

## Key findings

- Hexagonal boron nitride single photon emitters originate from carbonized organic residues.
- Nanoscale FTIR reveals aromatic carbon bonds at 1650 cm–1 in emission sites.
- Emitters are localized in encapsulated areas, not uniformly distributed in hBN.

## Abstract

Quantum light sources in van der Waals solid systems
operating
at room temperature have drawn significant attention, among which,
with particular interest, is hexagonal boron nitride (hBN). Numerous
efforts have focused on producing reliable, bright, and controllable
single photon emitters (SPEs) in hBN. However, the identity of these
emitters remains ambiguous, leading to unreproducible experimental
results. Here, we offer direct evidence that hBN SPEs generated through
annealing are not inside the hBN itself but originate from organic
residues that carbonize and form aromatic fluorophores. Nanoscale
Fourier transform infrared spectroscopy is used to analyze the emission
sites, revealing the presence of carbon bonds in aromatic rings with
a characteristic CC absorption peak at 1650 cm–1. These emitters are primarily located in encapsulated areas of the
hBN flake rather than uniformly distributed within the lattice. This
finding opens the door to designing stable and reliable SPEs, enabling
their integration into the rapidly growing quantum photonics applications.