@phdthesis{digilib72903,
           month = {August},
           title = {PENGARUH STONE-WALES DEFECT TEHADAP SIFAT OPTIK MONOLAYER h-BN MENGGUNAKAN DENSITY FUNCTIONAL THEORY},
          school = {UIN SUNAN KALIJAGA YOGYAKARTA},
          author = {NIM.: 21106020001 Priyo Prasetyo},
            year = {2025},
            note = {Dr. Widayanti, S. Si., M.Si dan Sri Hidayati, M.Sc.},
        keywords = {Density Functional Theory, H-BN, Stone-Wales Defect, Struktur Elektronik, Sifat Optik},
             url = {https://digilib.uin-suka.ac.id/id/eprint/72903/},
        abstract = {Hexagonal boron nitride (h-BN) is a two-dimensional material that possesses a range of unique properties, including mechanical stability, chemical stability, thermal stability, semiconducting behavior, ultraviolet absorption, and biocompatibility. These characteristics give h-BN potential for applications across various fields, one of which is photonic devices. Photonic devices based on h-BN can be broadened and optimized through defect engineering, such as stone?wales defects, which can significantly alter the properties of h-BN. This study investigates the influence of stone?wales defects on the properties of monolayer hexagonal boron nitride (h-BN) through density functional theory (DFT) calculations. The objective is to analyze the geometric structure, electronic structure, and optical properties of monolayer h-BN with stone?wales crystal defects. The calculations employ the generalized gradient approximation (GGA) exchange-correlation functional based on the Perdew?Burke?Ernzerhof (PBE) formulation, with ultrasoft pseudopotentials. Convergence tolerance parameters are set to 10-5 eV/atom for energy, 0.03 eV/{\r A} for maximum force, 0.05 GPa for maximum stress, and 0.001 {\r A} for maximum atomic displacement. The Stone?Wales defect model is constructed by rotating one boron?nitrogen bond by 90?. Geometrically, this defect generates two pentagonal and two heptagonal rings, reduces the system's point group symmetry to C{$_1$}h, and causes variations in bond lengths and nearest-neighbour atomic distances. Stone-wales defects can form new energy levels in the electronic structure of monolayer h-BN, thereby reducing the electronic bandgap to 3.303 eV. In the optical properties, stone-wales defects cause redshift in the absorption to 382 nm, along with a reduction in the optical band gap to 3.238 eV and reduction absorption peak. These results suggest that stone?wales defects significantly alter the intrinsic properties of pristine monolayer h-BN, potentially enhancing its application in photonic devices, particularly for quantum emitter applications.}
}