Electron-phonon coupling and localization of excitons in single silicon nanocrystals.
We report a detailed photoluminescence (PL) study on single silicon nanocrystals produced by laser pyrolysis. The PL spectra reveal nearly homogeneously broadened zero-phonon lines coupled to Si-O-Si phonon transitions in the SiO2 shell. A systematic investigation of electron-phonon coupling is reported on the basis of single nanocrystals. The stepwise localization of electron and hole at the Si-SiO2 interface for nanocrystals smaller than d approximately 2.7 nm is driven by electron-phonon coupling. From the localization energies the effective Bohr radii of the (localized) electron and hole are estimated to be in the range of 1-2 bond lengths of Si-O and Si-Si.
Martin
Jörg
J
Institute of Physics and nanoMA, Chemnitz University of Technology, D-09107 Chemnitz, Germany.
Cichos
Frank
F
Huisken
Friedrich
F
von Borczyskowski
Christian
C
D003198:Computer Simulation; D004553:Electric Conductivity; D004579:Electron Transport; D004583:Electrons; D008027:Light; D008422:Materials Testing; D008956:Models, Chemical; D049329:Nanostructures / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods*; D010316:Particle Size; D017785:Photons; D011829:Radiation Dosage; D012825:Silicon / Q000737:chemistry*
D012825:Silicon