Article

Coherent and phonon-assisted tunnelling in asymmetric double barrier resonant tunnelling structures.

Australian Journal of Physics 01/2000; DOI: 10.1071/PH99037

ABSTRACT We present a theory for calculating the phonon-assisted tunnelling current in
asymmetric double barrier resonant tunnelling structures (DBRTS), in which all
of the phonon modes including the interface modes and the confined bulk-like
LO phonons and the conduction band nonparabolicity are considered. An
important physical picture about coherent and phonon-assisted tunnelling is
given. The coherent tunnelling current can be directly determined by both the
width of the resonant level and the peak value of the transmission coecient at
the resonant level. The phonon-assisted tunnelling current mainly comes from
electron interaction with higher frequency interface phonons (especially the
interface phonons localised at either interface of the left barrier).
Phonon-assisted tunnelling makes a significant contribution to the valley
current. The subband nonparabolicity strongly influences on
electron–phonon scattering and current-to-voltage characteristics. A
specially designed asymmetric DBRTS may have an improved performance over the
symmetric DBRTS.

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