Department of Physics; Material Science Institute; Center for Optical, Molecular, and Quantum Science , University of Oregon , Eugene , Oregon 97403 , United States.
Department of Physics , Hamilton College , Clinton , New York 13323 , United States.
Nano Lett. 2019 Mar 13;19(3):2121-2127. doi: 10.1021/acs.nanolett.9b00357. Epub 2019 Feb 20.
Quantum emitters (QEs) in 2D hexagonal boron nitride (hBN) are extremely bright and are stable at high temperature and under harsh chemical conditions. Because they reside within an atomically thin 2D material, these QEs have a unique potential to couple strongly to hybrid optoelectromechanical and quantum devices. However, this potential for coupling has been underexplored because of challenges in nanofabrication and patterning of hBN QEs. Motivated by recent studies showing that QEs in hBN tend to form at edges, we use a focused ion beam (FIB) to mill an array of patterned holes into hBN. Using optical confocal microscopy, we find arrays of bright, localized photoluminescence that match the geometry of the patterned holes. Furthermore, second-order photon correlation measurements on these bright spots reveal that they contain single and multiple QEs. By optimizing the FIB parameters, we create patterned single QEs with a yield of 31%, a value close to Poissonian limit. Using atomic force microscopy to study the morphology near emission sites, we find that single QE yield is highest with smoothly milled holes on unwrinkled hBN. This technique dramatically broadens the utility and convenience of hBN QEs and achieves a vital step toward the facile integration of the QEs into large-scale photonic, plasmonic, nanomechanical, or optoelectronic devices.
二维六方氮化硼（hBN）中的量子发射器（QEs）极其明亮，在高温和恶劣的化学条件下也能保持稳定。由于它们位于原子级薄的二维材料中，因此这些 QE 具有与混合光电机械和量子器件强耦合的独特潜力。然而，由于 hBN QE 的纳米制造和图案化方面的挑战，这种耦合的潜力尚未得到充分探索。受最近的研究表明 hBN 中的 QE 倾向于在边缘形成的启发，我们使用聚焦离子束（FIB）在 hBN 中刻蚀出一系列图案化的孔。使用光学共焦显微镜，我们发现了一系列明亮的、局域化的光致发光，这些光致发光与图案化孔的几何形状相匹配。此外，对这些亮点进行的二阶光子相关测量表明，它们包含单个和多个 QE。通过优化 FIB 参数，我们以 31%的产率创建了图案化的单 QE，接近泊松极限。通过原子力显微镜研究发射点附近的形态，我们发现，在未起皱的 hBN 上，采用光滑铣削孔的方式可使单 QE 的产率达到最高。这项技术极大地拓宽了 hBN QE 的实用性和便利性，并朝着将 QE 轻松集成到大规模光子学、等离子体学、纳米机械学或光电设备的方向迈出了重要一步。
