Akademik Veri Yönetim Sistemi
Journal of Luminescence, cilt.297, 2026 (SCI-Expanded, Scopus)
In this work, we present a theoretical investigation of the electronic and optical properties of hydrogenic donor impurities in spherical Ge1-xSnx/CdS core/shell quantum dots under the combined effects of tin composition, dielectric environment, and external electric field. Calculations were conducted under the effective mass approximation, taking into account strain-induced band offsets, dielectric mismatch effects, and quantum confinement. The variation of impurity binding energy and photoionization cross-section with respect to structural parameters such as core-shell radius ratio, Sn concentration, and surrounding matrix permittivity, and external parameters such as electric field, was systematically analyzed. Our results show that increasing Sn content enhances the binding energy and significantly modifies the optical response due to bandgap reduction and effective mass variation. The dielectric environment strongly influences the impurity states through Coulomb screening, leading to higher binding energies in low-permittivity matrices. Furthermore, the application of an external electric field induces a pronounced Stark effect, resulting in a reduction of the impurity binding energy and a noticeable shift and suppression of the photoionization peaks. These findings demonstrate that the optoelectronic features of GeSn/CdS core/shell quantum dots can be efficiently tuned via composition engineering, dielectric confinement, and electric field control, making these nanostructures promising candidates for advanced optoelectronic and infrared photonic applications.