Resonant interband tunneling current in InAs/AlSb/GaSb/AlSb/InAs double barrier diodes

We have investigated the resonant interband tunneling currents (I-RIT) in InAs/AlSb/GaSb/AlSb/InAs double-barrier resonant interband tunneling diodes. We have prepared samples with various thicknesses of the GaSb well (L-w) ranging from 5 to 47 monolayers (ML) and various thicknesses of the AlSb barrier (L-b) ranging from 0 to 5 ML, and analyzed the dependence of I-RIT on these thicknesses. As L-w increases, I-RIT increases if L-w is smaller than a certain boundary value of L-w (L-w(b)), but I-RIT decreases if L-w is larger than L-w(b). We have found that this boundary value L-w(b) depends on L-b, that is, L-w(b) decreases from 23 to 10 ML when L-b changes from 0.5 to 5 ML. Furthermore, we have also found that, for constant L-w, I-RIT increases as L-b increases to a certain boundary value of L-b, and I-RIT decreases for further increase in L-b. These marked behaviors of L-w(b) and IRIT on L-b are characteristic of the type II material systems and cannot be explained by the conventional model applied to type I resonant tunneling diodes. To explain these characteristic behaviors, we propose a model where the resonance level in the valence band of the GaSb well moves up toward the valence-band edge with an increase in L-b. (C) 1998 American Institute of Physics.