Wu Yuanpeng, Xiao Yixin, Zhao Ying, Shen Yifan, Sun Kai, Wang Boyu, Wang Ping, Wang Ding, Zhou Peng, Wang Danhao, Liu Jiangnan, Hu Mingtao, B Norris Theodore, Song Jun, Mi Zetian
Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI 48109.
Department of Mining ang Materials Engineering, McGill University, Montreal, QC H3A 0C5, Canada.
Proc Natl Acad Sci U S A. 2025 Mar 4;122(9):e2417859122. doi: 10.1073/pnas.2417859122. Epub 2025 Feb 25.
Semiconductor quantum dots (QD) promise unique electronic, optical, and chemical properties, which can be exquisitely tuned by controlling the composition, size, and morphology. Semiconductor QDs have been synthesized primarily via two approaches, namely, epitaxial growth and wet-chemical synthesis. However, the properties of epitaxial QDs (eQDs) are susceptible to wetting layer formation and substrate dislocations, while colloidal QDs (cQDs) face fluorescence intermittency issues. Here, we report on the synthesis of a class of QDs that can overcome the fundamental limitations of eQDs and cQDs. By exploiting the sp bonding of layered hexagonal boron nitride (hBN), we show that GaN QDs can be epitaxially grown through a weak van der Waals (vdW) interaction without two-dimensional wetting layer formation. The photoluminescence intensity of GaN van der Waals quantum dots (vQDs) is more than six times stronger than that of conventional GaN eQDs and no optical blinking was observed from vQDs. We show that the interadatom bond strength is about one order of magnitude stronger compared with that between the adatoms and the hBN substrate. This work shows that vQDs have unique properties that are difficult to achieve using existing QDs synthesis methods and thus can potentially enable new classes of high-performance optoelectronic and quantum devices.
半导体量子点（QD）具有独特的电学、光学和化学性质，通过控制其组成、尺寸和形态可以对这些性质进行精确调控。半导体量子点主要通过两种方法合成，即外延生长和湿化学合成。然而，外延量子点（eQD）的性质易受润湿层形成和衬底位错的影响，而胶体量子点（cQD）则面临荧光间歇性问题。在此，我们报道了一类能够克服eQD和cQD基本局限性的量子点的合成。通过利用层状六方氮化硼（hBN）的sp键，我们表明氮化镓量子点（GaN QD）可以通过弱范德华（vdW）相互作用外延生长，而不会形成二维润湿层。氮化镓范德华量子点（vQD）的光致发光强度比传统的GaN eQD强六倍以上，并且未观察到vQD的光学闪烁现象。我们表明，与吸附原子和hBN衬底之间的键相比，原子间键强度大约强一个数量级。这项工作表明，vQD具有现有量子点合成方法难以实现的独特性质，因此有可能实现新型高性能光电器件和量子器件。
