Abstract
We demonstrate that the current through a double barrier heterostructure is independent of whether the electron tunneling mechanism is sequential or Fabry–Perot like. For typical experimental parameters we show that inelastic scattering, which destroys the phase coherence, is an important effect that strongly reduces the probability for coherent tunneling. As a result, the tunneling will be mainly incoherent (sequential). However, in a model calculation where the degree of coherency can be varied, we find that the tunneling current does not depend on which of the two mechanisms dominate as long as the resonant energy is well defined.