Singla Sakal, Joshi Pragya, López-Morales Gabriel I, Sarkar Suman, Sarkar Suman, Flick Johannes, Chakraborty Biswanath
Department of Physics, Indian Institute of Technology Jammu, Jammu 181221, India.
Department of Physics, City University of New York, New York, New York 10031, United States.
Nano Lett. 2024 Jul 31;24(30):9212-9220. doi: 10.1021/acs.nanolett.4c01477. Epub 2024 Jun 18.
Optically bright emitters in hexagonal boron nitride (hBN) often acting as a source of a single-photon are mostly attributed to point-defect centers, featuring localized intra-bandgap electronic states. Although vacancies, anti-sites, and impurities have been proposed as candidates, the exact physical and chemical nature of most hBN single-photon emitters (SPEs) within the visible region are still up for debate. Combining site-specific high-angle annular dark-field imaging (HAADF) with electron energy loss spectroscopy (EELS), we resolve and identify a few carbon substitutions among neighboring hBN hexagons, all within the same sample region, from which typical defect emission is observed. Our experimental results are further supported by first-principles calculations, through which the stability and possible optical transitions of the proposed carbon-defect complex are assessed. The presented correlation between optical emission and defects provides valuable information toward the controlled creation of emitters in hBN, highlighting carbon complexes as another probable cause of its visible SPEs.
六方氮化硼（hBN）中通常作为单光子源的光学亮发射体大多归因于点缺陷中心，其具有局域化的带隙内电子态。尽管空位、反位和杂质已被提出作为候选者，但可见区域内大多数hBN单光子发射体（SPE）的确切物理和化学性质仍有待讨论。结合特定位置的高角度环形暗场成像（HAADF）和电子能量损失谱（EELS），我们在同一样品区域内解析并识别了相邻hBN六边形中的一些碳取代，从中观察到典型的缺陷发射。我们的实验结果得到了第一性原理计算的进一步支持，通过该计算评估了所提出的碳缺陷复合体的稳定性和可能的光学跃迁。所呈现的光发射与缺陷之间的相关性为hBN中发射体的可控创建提供了有价值的信息，并突出了碳复合体作为其可见SPE的另一个可能原因。
