INADEQUACY OF THE ONE-DIMENSIONAL APPROXIMATION FOR RESONANT-TUNNELING-DIODE CURRENT-VOLTAGE CALCULATIONS

Evaluating the full expression for the tunneling current density in a resonant-tunneling diode generally involves the numerical computation of a triple integral. Since this presents such a formidable task, quite often one neglects any explicit dependence of the transmission coefficient on the wave vector in the plane of the interfaces, k, resulting in a single-integral expression. This one-dimensional approximation has been widely used in the literature. We demonstrate that this approximation, even when applied to rather ordinary devices, can lead to unphysical current-density bias graphs and explain the reasons behind the failure. © 1995 The American Physical Society.