GAMMA-TO-X(Z) ELECTRON-TRANSFER TIMES IN TYPE-II SUPERLATTICES DUE TOEMISSION OF CONFINED PHONONS

We calculate the GAMMA --> X(z) electron transfer times due to the emi ssion of confined longitudinal optical phonons in type-II GaAs-AlAs an d AlGaAs-AlAs superlattices. A dielectric continuum model is employed to describe the electron-confined-phonon interaction and the electron envelope wave functions are obtained from a Kronig-Penney model. The c alculated transfer times compare within order of magnitude, or better, with available experimental results and we obtain a good qualitative description of the transfer time dependence on the layer thicknesses.