Abstract
We investigate the electron-hole interactions in spherical silicon nanocrystals by incorporating Coulomb, exchange, and spin-orbit couplings into a tight-binding model. We study the effect of the electron-hole attraction on the absorption spectra and on the dielectric constant, using a real-time propagation technique. Diagonalizing the full fine-structure Hamiltonian for two-particle states close to the band gap gives exchange splittings that range from $\ensuremath{\sim}100$ to 7 meV for nanocrystals of radii 6--18 \AA{}. The splittings persist in the presence of spin-orbit coupling for nanocrystals of radius up to 18 \AA{}, suggesting that dark triplet states below the absorption threshold can be the origin of the Stokes shifts and temperature-dependent lifetimes observed in luminescence experiments.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
