ELECTRON PHONON INTERACTION IN GAAS/ALXGA1-XAS/GAAS SINGLE-BARRIER HETEROJUNCTION DIODES

We have investigated the effect of electron-phonon interaction during the tunneling process in GaAs/AlGaAs/GaAs heterojunction tunneling structures by measuring the first ( dI dV) and the second ( d2I dV2) derivative spectra of tunneling current at 4.2 K. We observe cusplike conductance decreases in both bias polarities near the energies of optical phonons in GaAs and AlGaAs. It is found that in the vicinity of the electrode-barrier interface the electronic dispersion in the GaAs electrodes is strongly modified by the interaction not only with longitudinal optical phonons in the GaAs electrodes but also with the interface phonons at the electrode-barrier interfaces. On the contrary, structures due to phonon-assisted process in the barrier were observed in the d2I dV2 spectra on GaAs/AlAs/GaAs diodes. © 1990.