Direct Visualization and Effects of Atomic‐Scale Defects on the Optoelectronic Properties of Hexagonal Boron Nitride

Hexagonal boron nitride (hBN) has attracted a lot of attention in the past years, thanks to its many remarkable properties. These include the presence of single-photon emitters with superior optical properties, which make it an ideal candidate for a plethora of photonic technologies. However, despite the large number of experimental results and theoretical calculations, the structure of the defects responsible for the observed emission is still under debate. In this work, individual atomic-scale defects in hBN with atomic force microscopy under ambient conditions are visualized and multiple narrow emission lines from optically stable emitters are observed. This direct observation of the structure of the defects combined with density functional theory calculations of their band structures and electronic properties allows associating the existence of several single-photon transitions to the observed defects. The work sheds light on the origin of single-photon emission in hBN that is important for the understanding and tunability of high-quality emitters in optoelectronics and quantum technologies.