INTERFACE PHONONS IN GAAS ALAS QUANTUM DOTS

Electron scattering by interface phonon modes in GaAs/AlAs quantum dot s is investigated. The emission rates are calculated using an electron -phonon interaction Hamiltonian derived in the framework of the dielec tric continuum model. The effect of the embedding material AlAs on the electron relaxation by interface phonons is analyzed by comparing the emission rates with those obtained for GaAs free standing quantum dot s in vacuum. This effect reduces the emission rates yielding relaxatio n times slower than the radiative recombination lifetime of electrons and holes in their ground levels. In GaAs/AlAs quantum dots, it appear s that the contribution of the electron relaxation via interface phono n emission to the radiative decay processes is less significant than t he relaxation mechanisms via longitudinal optical and longitudinal aco ustic phonon. Faster relaxation times are obtained if the interface ph onon mode involved in the scattering processes is antisymmetric. (C) 1 995 Academic Press Limited