Role of LO Phonons in Optical Spectra of Quantum Dot Aggregates in Sub-Wetting Layer Region of Energy

Samples of the self-assembled polar semiconductor quantum dots, grown by the Stranski–Krastanow growth method, contain the wetting layer, representing the lowest barrier for the electronic excitations to get to the extended motion states. The scattering of electrons between the extended states and the electronic states localized in the individual quantum dots, with emission or absorption of optical phonons via Fröhlich's coupling, may influence the optical spectra of such samples in the sub-wetting layer region of the energy of electronic excitations. The contribution of this interaction to the appearance of the sub-wetting layer continuum in the optical spectra and to the level broadening of the localized states, is studied.