Wannier-Stark effect and electron-phonon interaction in macroporous silicon structures with Si02 nanocoatings.

Abstract

We investigated the contribution ofelectron-phonon interaction to the broadening parameter T of the Wannier-Stark ladder levels in oxidized macroporous silicon structures with different concentration ofSi-O-Si states (TO and LO phonons). The obtained value of the Wannier-Stark ladder parameter ris much less than the djacent level energy evaluated from giant oscillations of resonance electron scattering on the surface states. We determined the influence of broaden ing on the oscillation amplitude in IR absorption spectra as interaction of the surface multi-phonon polaritons with scattered electrons. This interaction transforms the resonance electron scattering in samples with low concentration ofSi-O-Si states into ordinary scattering on ionized impurities for samples with high concentration ofSi-O-Si states. The transformation takes place at the scattering lifetime coinciding with the period of electron oscillations in the surface electric field.