THEORETICAL INVESTIGATIONS OF RESONANT-TUNNELING IN ASYMMETRIC MULTIBARRIER SEMICONDUCTOR HETEROSTRUCTURES IN AN APPLIED CONSTANT ELECTRIC-FIELD

We solve the one-dimensional Schrodinger wave equation in the effectiv e-mass approximation for the transmission coefficient T(E) of electron s through asymmetric multibarrier semiconductor heterostructures in th e presence of a constant applied electric field, using an exact Airy-f unction formalism and the transfer-matrix technique. In particular, we show that for appropriate choices of asymmetry in the barrier widths and heights of the semiconductor heterostructure, the transmission coe fficient is enhanced to yield resonances that are stronger than those calculated in symmetric structures, thus giving further validity to Me ndez's concept of effective-barrier symmetry for obtaining optimal res onant tunneling in asymmetric double- and triple-barrier semiconductor heterostructures. These results should assist experimental efforts in designing resonant-tunneling systems that require optimum peaks both in the transmission spectrum and current density.