Fischer Moritz, Sajid Ali, Iles-Smith Jake, Hötger Alexander, Miakota Denys I, Svendsen Mark K, Kastl Christoph, Canulescu Stela, Xiao Sanshui, Wubs Martijn, Thygesen Kristian S, Holleitner Alexander W, Stenger Nicolas
Department of Electrical and Photonics Engineering, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark.
Centre for Nanostructured Graphene, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark.
Nanoscale. 2023 Sep 1;15(34):14215-14226. doi: 10.1039/d3nr01511d.
The two-dimensional material hexagonal boron nitride (hBN) hosts luminescent centres with emission energies of ∼2 eV which exhibit pronounced phonon sidebands. We investigate the microscopic origin of these luminescent centres by combining calculations with non-perturbative open quantum system theory to study the emission and absorption properties of 26 defect transitions. Comparing the calculated line shapes with experiments we narrow down the microscopic origin to three carbon-based defects: CC, CC, and VC. The theoretical method developed enables us to calculate so-called photoluminescence excitation (PLE) maps, which show excellent agreement with our experiments. The latter resolves higher-order phonon transitions, thereby confirming both the vibronic structure of the optical transition and the phonon-assisted excitation mechanism with a phonon energy ∼170 meV. We believe that the presented experiments and polaron-based method accurately describe luminescent centres in hBN and will help to identify their microscopic origin.
二维材料六方氮化硼（hBN）含有发射能量约为2 eV的发光中心，这些发光中心表现出明显的声子边带。我们通过将计算与非微扰开放量子系统理论相结合，研究了26种缺陷跃迁的发射和吸收特性，以探究这些发光中心的微观起源。通过将计算得到的线形与实验结果进行比较，我们将微观起源缩小到三种碳基缺陷：CC、CC和VC。所开发的理论方法使我们能够计算所谓的光致发光激发（PLE）图谱，其与我们的实验结果显示出极好的一致性。后者解析了高阶声子跃迁，从而证实了光学跃迁的振动电子结构以及声子能量约为170 meV的声子辅助激发机制。我们相信，所展示的实验和基于极化子的方法能够准确描述hBN中的发光中心，并将有助于确定其微观起源。
