Direct experimental determination of the tunnelling time and transmission probability of electrons through a resonant tunnelling structure

Abstract

A sharp step-like structure, which is seen in the current-voltage characteristic of a laterally confined AlGaAs/GaAs resonant tunnelling structure, is a novel manifestation of a quantum effect arising when one-dimensional wires feed electrons into a zero-dimensional quantum box. The authors can analyse the data to deduce a tunnelling time, an inelastic scattering time and the transmission probability for electrons in this system. The height of the current steps, Delta I, gives the electron tunnelling time, taue, via Delta I=e/2 taue, while the differential conductance gives the peak transmission probability, T0, via G approximately (e2/h)T0. The authors must invoke inelastic scattering to explain the low value of T0 approximately 9% obtained from the data, and so they find that tunnelling in their structure is sequential.