  Single photon emitters in two-dimensional (2D) hexagonal boron nitride (hBN)
are promising solid-state quantum emitters for photonic applications and
quantum networks. Despite their favorable properties, it has so far remained
elusive to determine the origin of these emitters. We focus on two different
kinds of hBN samples that particularly lend themselves for integration with
nanophotonic devices, multilayer nanoflakes produced by liquid phase
exfoliation (LPE) and a layer engineered sample from hBN grown by chemical
vapour deposition (CVD). We investigate their inherent defects and fit their
emission properties to computationally simulated optical properties of likely
carbon-related defects. Thereby we are able to narrow down the origin of
emitters found in these samples and find that the C2CB defect fits our spectral
data best. In addition, we demonstrate a scalable way of coupling LPE hBN to
optical nanofibers that are directly connected to optical fibers. Our work
brings us one step closer to specifying the origin of hBN's promising quantum
emitters and sheds more light onto the characteristics of emitters in samples
that are particularly suited for integration with nanophotonics. This knowledge
will prove invaluable for novel nanophotonic platforms and may contribute
towards the employment of hBN for future quantum technologies.
