Title : Impact of Point Defects on the Photoluminescence line shapes and Raman Properties of 2D h-BN from density functional theory calculationsOral : Impact of Point Defects on the Photoluminescence line shapes and Raman Properties of 2D h-BN from density functional theory calculations

Hexagonal boron nitride (h-BN) is emerging as a host material in quantum photonics, offering potential for stable photon emission at room temperature. Defect engineering in h-BN is crucial for tuning its optical properties, as specific defects can significantly influence excitation and emission processes, enabling advanced applications. Despite significant progress, opportunities remain for discovering new point defects at various concentrations. This study employs density functional theory (DFT) to examine the effects of defects, including dopants (C, Si), antisites, and vacancies, on the photonic properties of 2D h-BN. Key parameters such as the zero-phonon line energy (E_ZPL) and the Huang-Rhys (HR) factor were calculated to understand emission without vibrational coupling and the strength of electron-phonon interaction. Additionally, the change in the configuration coordinate, ΔQ, between the ground and excited states was computed. Raman spectra confirmed the structural integrity and vibrational characteristics of these configurations. The introduction of defects reduced the E_ZPL by up to 1.1 eV compared to pristine h-BN (5.09 eV), indicating an emission range between near-infrared (IR) and near-ultraviolet (UV), with small HR factors (~0.84), suggesting minimal structural distortion and weak electron-phonon interaction. These findings suggest that defect-engineered h-BN is promising for quantum emitters, nanophotonics, and sensing technologies.