Abstract
The dynamical features of an electron wave packet tunneling through a double-barrier-quantum-well (DBQW) structure with a defect-layer sheet on the barrier are studied using the transfer-matrix approach. We examine the time dependence of the probability density (t) of finding an electron inside the well, and find that the behavior of (t) is quite diverse for different systems. It depends on the momentum distribution of the incident electron and the structure of the quasibound states in the well, modulated by the defect-layer sheet on the barrier. In particular, (t) may oscillate with time. To explain this oscillating behavior, we analyze the electron wave function in the well in detail and present a physical picture to describe the motion of the electron wave packet within the well. For comparison, the equivalent DBQW structure without a localized state is also investigated. Our results indicate that the dwell time can be significantly shortened by introducing a localized state inside the barrier. This result may find application in the design of fast devices.
- Received 29 April 1991
DOI:https://doi.org/10.1103/PhysRevB.44.8204
©1991 American Physical Society