Electron-phonon interaction in non-polar quantum dots induced by the amorphous polar environment

We propose a Fröhlich-type electron-phonon interaction mechanism for carriers confined in a non-polar quantum dot surrounded by an amorphous polar environment. Carrier transitions under this mechanism are due to their interaction with the oscillating electric field induced by the local vibrations in the surrounding amorphous medium. We estimate the corresponding energy relaxation rate for electrons in Si nanocrystals embedded in a SiO$_2$ matrix as an example. When the nanocrystal diameter is larger than $4$ nm then the gaps between the electron energy levels of size quantization are narrow enough to allow for transitions accompanied by emission of a single local phonon having the energy about 140 meV. In such Si/SiO$_2$ nanocrystals the relaxation time is in nanosecond range.