Time Dependent Tunneling in Double-Barrier ZnSe/ZnTe Structures

Abstract

Recently there has been great both experimental [1] and theoretical interest [2] in quantum tunneling devices. However, the dynamical aspects of tunneling, although important for the physical understanding as well as for applications, have remained largely unclear [3]. Most theoretical works concerning resonant tunneling involve time independent methods such as finding eigenvalues for quantum wells and superlattice stuctures. The transmission probability for such stuctures is usually calculated using plane wave approximation and this gives no information about time resolution of tunneling process. Recent experimental techniques allow measurement of the tunneling time in double quantum wells and, thus, provide information about maximum switching frequency of such devices [4]. In this paper we deal with a time dependent quantum mechanics of a wave packet to calculate the tunneling probability for a double-barrier stucture n-type ZnSe/p-type ZnTe. The energy diagram of the structure is presented in the insert in Fig. 1. The electron is treated in full quantum mechanical way within the effective mass approximation. The detailed electron dynamics is obtained by solving the time dependent Schrodinger equation