Effects of interface phonon scattering in three-interface heterostructures

A detailed study of the electron-optical-phonon interaction in an asymmetric one-well/one-barrier heterostructure is given. Dispersion relations and phonon potential distributions for interface phonon modes are derived in the framework of the macroscopic dielectric continuum model. It is found that for intrawell relaxation processes the sum of the scattering rates by all interface polar-optical phonon modes is approximately independent of the width of the barrier layer. Consequently, a simplified Hamiltonian for electron-phonon interaction in a single quantum well can be used for scattering rate calculation in multiple heterointerface structures. The combined scattering rates by interface and confined phonon modes are compared with the results obtained in an idealized model using the bulklike phonon spectrum. The practical invalidity of the latter approximation is shown for electron kinetic energies comparable with the typical energy of optical phonons in the heterostructure. (C) 1998 American Institute of Physics.