Electrical and optical properties of C, Ge-doped armchair silicene nanoribbons applied in optoelectronics

Abstract

With the continuous development of nanotechnology, the search for new material structures plays a crucial role. Silicene nanoribbons are one-dimensional materials that hold promise for numerous potential applications in the future. The electric and optical properties of C, Ge-doped armchair silicene nanoribbons are investigated in this study using Density Functional Theory (DFT). All the doped configurations are stable and maintain the honeycomb hexagonal structure after optimization. Doping with C yields flatter structures, while doping with Ge yields larger buckling heights. The C 1-1 doping configuration is highlighted because its band gap is extended up to 2.35 eV, making it an ideal candidate for potential optoelectronic applications. The charge distribution, charge density difference, and hybridization of multiple orbitals are also systematically studied. The optical properties reveal the differences between C and Ge doping, with a clear anisotropy observed. Strong absorption occurs at high electromagnetic wave energies,, while the absorption coefficient rapidly decreases in the long-wavelength range. The study of electron-hole density shows good agreement with the energy band structure, where electron-hole pairs only exist when the excitation energy is greater than the bandgap width, and not all excitation energy values give rise to electron-hole pairs. This study contributes a small part to creating potential applications in nanotechnology.