Current-voltage calculations for InAs/AlSb resonant-tunneling diodes

One expects that the one-dimensional approximation for the resonant-tunneling-diode tunneling current should be very accurate in the InAs/AlSb materials system, with its large barriers and largely Γ-like tunneling. We study this approximation as well as the two-dimensional expression, which takes into account the explicit dependence of the transmission coefficient on the magnitude of the in-plane wave vector ${\mathbf{k}}_{\mathrm{\parallel }}$. We find that even here the one-dimensional approximation fails, producing curves that are qualitatively very different from those of the two-dimensional approximation and study the reasons for the differences. We also briefly examine the angular dependence of the transmission coefficients, the results indicating that the two-dimensional approximation is likely to be fairly good for the structures studied.