Multibarrier tunneling in Ga1−xAlxAs/GaAs heterostructures

A theoretical study of resonant tunneling in multilayered Ga1−xAlxAs/GaAs structures is presented. The spectrum of resonant energies and its dependence on the barrier structure are analyzed from calculated profiles of barrier transparency versus energy, and from current–voltage characteristics computed at selected temperatures and Fermi levels. The present formalism is based on the effective mass approximation as done to date, but contains three significant improvements: a more realistic treatment of the spatial dependence of effective masses and band edges; the recognition of the special dynamical role played by the transverse energy as a consequence of the difference in itinerant two dimensional carrier motion from layer to layer; and the avoidance of plane-wave or WKB approximations for calculating the wave function in favor of direct numerical evaluation. It is shown that these revisions lead to quantitative differences with results of previous work.