First-Principles Investigation of Erbium Doping and Intrinsic Defects on the Structural and Electronic Properties of Silicon Dioxide | ||
| Progress in Physics of Applied Materials | ||
| مقاله 8، دوره 5، شماره 2 - شماره پیاپی 9، بهمن 2025، صفحه 175-185 اصل مقاله (1.71 M) | ||
| نوع مقاله: Original Article | ||
| شناسه دیجیتال (DOI): 10.22075/ppam.2025.37283.1142 | ||
| نویسندگان | ||
| Adeyemi Joshua Owolabi* 1؛ Haruna Ali1؛ Mohammed Yusuf Onimisi1؛ Benedict Machu1؛ Alhassan Shuaibu2؛ Isaac Hyuk Daniel2؛ Mary Samuel3؛ Olalekan Joel Awujoola4 | ||
| 1Department of Physics, Nigerian Defence Academy, Kaduna, Nigeria | ||
| 2Department of Physics, Kaduna State University, Kaduna, Nigeria | ||
| 3Department of Mechanical Engineering Nigerian Defence Academy, Kaduna, Nigeria | ||
| 4Department of Computer Science, Nigerian Defence Academy, Kaduna | ||
| چکیده | ||
| Rare-earth-doped silica (SiO₂) nanostructures have great potential for optoelectronics but little is known about the atomic-scale processes controlling their electrical behaviour in the presence of intrinsic defects and erbium (Er) doping. In order to close this gap, this work uses the Density Functional Theory with Generalized Gradient Approximation (DFT-GGA), a first-principles density functional theory, to analyse the structural and electrical changes in Er-doped SiO₂ and its defective forms. Er was used to replace Si atoms in three doping concentration models of 2.08%, 4.17%, and 6.25%, for silicon vacancies (SiV) and oxygen vacancies (OV), which were added to evaluate defect-mediated effects. Lattice expansion proportionate to Er concentration was found by structural optimisation, which was driven by Er–O bonds of 2.1 – 2.3 Å and larger ionic radius 2.45 Å and 1.46 Å for Si. Thermodynamic stability was demonstrated by formation energies ranging from -0.675 to -0.724 eV/atom, where lower energy configurations were preferred by increased Er content. Er 4f, which derives the impurity states near the conduction band, is responsible for the transition to a direct band gap. The band structure calculations show moderate Er doping at 4.17%, which shows SiO₂’s indirect band gap of 5.32 eV to the doped indirect band gap of 5.98 eV and direct band gap of 5.01 and 5.08 eV. Due to dopant interactions changing of the host matrix, the gap unexpectedly extended to 5.89 eV at 6.25% Er concentration. Oxygen and silicon vacancies further modulated electronic properties, introducing deep donor levels and reducing the gap of OV to 3.89 eV and SiV to 4.21 eV formation energy albeit at significant energetic costs. Density of states analysis highlighted hybridization between Er 4f and 5d orbitals and host O 2p and Si 3p states, enabling tailored band engineering. This work establishes a theoretical framework linking Er doping and defects to tunable electronic properties in SiO₂, offering insights for designing high-efficiency optoelectronic materials. | ||
| کلیدواژهها | ||
| Erbium Doping؛ Silica Nanostructures؛ DFT-GGA؛ Band Gap؛ Intrinsic Defects؛ Optoelectronics | ||
| مراجع | ||
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