PHONON-ASSISTED TUNNELING DUE TO LOCALIZED MODES IN DOUBLE-BARRIER STRUCTURES

The excess current associated with phonon-assisted tunneling at low temperature in GaAs/AlAs double-barrier resonant-tunneling structures is calculated taking into account localized phonon modes. We find that symmetric interface phonon modes generate the most current in a typical structure, while confined modes in the GaAs well also contribute significantly. Antisymmetric interface modes and confined modes in AlAs barrier layers generate much less current. Numerical results are in unexpectedly close agreement with available experimental data.