EFFECTS OF THE LOCALIZED STATE INSIDE THE BARRIER ON RESONANT TUNNELING IN DOUBLE-BARRIER QUANTUM-WELLS

We analyze the doping effects on resonant tunneling of a defect-layer sheet on the barrier in double-barrier quantum wells, using the effective-mass approximation and transfer-matrix approach. The potential for defects is taken to be a -function model potential. When the local-state level for the defects matches one of the quasibound state levels in the quantum well (QW), a strong coupling between them occurs. It splits and shifts the original resonant peaks in the transmission probability. In the opposite case, no splitting of the peaks is observed but an extra resonant peak corresponding to the defect state appears and the shifting of peaks occurs. The degree of coupling also depends on the position of the defect layer relative to the barrier-well interface. The closer to the interface the defect layer is, the stronger the coupling is. It shows that the localized state level and the position of the defect layer may be additional growth-control parameters and can be used to modify the energy structures of the QW. © 1990 The American Physical Society.