Modeling of electron tunneling times in asymmetric double quantum wells

A scattering process modeled by an imaginary potential V _I in the wide well of an asymmetric double quantum well structure (DQWS) is used to model the electron tunneling from the narrow well. Taking V _I –5 meV, the ground resonant level lifetimes of the narrow well in the DQWS are in quantitative agreement with the experimental resonance and non-resonance tunneling times. The corresponding scattering time 66 fs is much faster than the intersubband scattering time of LO-photon emission.