Speaker
Description
Quantum emitters (QEs) play crucial roles in quantum technology applications, especially for quantum key distribution. Recently, color-center defects in a two-dimensional hexagonal boron nitride (hBN) have revealed many promising properties, such as high brightness, operation under room temperature, and broad emission wavelengths, demonstrating that they are attractive candidates for QEs. Thus far, most experiments found the emitter at 2 eV range influenced by C-based defects; however, the nature of defects for such QEs remains unknown and uncovered. In this work, we investigate 2 eV emitters using density functional theory (DFT) with Perdew-Burke-Ernzerhof (PBE) functional. We aim to theoretically characterize the origin of the electronic transition and to further identify the possible 2 eV defects. Four different types of defects, namely $C_BV_N$, $C_BC_N$, $N_BV_N$, and $O_BO_BV_N$ have been unraveled. Our results suggest that all of studied defects except for $C_BC_N$ are likely 2 eV emitters whereas $C_BC_N$ is more likely to be a 4 eV emitter. This paves the way that not only C-based defects, but also non C-based defects emit at 2 eV. Furthermore, our defect formation energy calculation predicts that $C_BC_N$ is the most thermodynamically favorable for synthesis, followed by $N_BV_N$, $O_BO_BV_N$ and $C_BV_N$.
