Combining experiments on luminescent centres in hexagonal boron nitride with the polaron model and ab initio methods towards the identification of their microscopic origin

Moritz Fischer, Ali Sajid, Jake Iles-Smith, Alexander Hötger, Denys I. Miakota, Mark K. Svendsen, Christoph Kastl, Stela Canulescu, Sanshui Xiao, Martijn Wubs, Kristian S. Thygesen, Alexander W. Holleitner, Nicolas Stenger

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

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 ab initio 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: C2CB, C2CN, and VNCB. 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.

Original languageEnglish
Pages (from-to)14215-14226
Number of pages12
JournalNanoscale
Volume15
Issue number34
DOIs
StatePublished - 16 Aug 2023

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