We have investigated the resonant interband tunneling current in InAs/AlSb/GaSb/AlSb/InAs double-barrier resonant interband tunneling diodes with extremely thin AlSb barriers. Although no negative differential resistance (NDR) was observed for the diode without AlSb barrier layers, NDR appeared when 0.5-monolayer(ML)-thick AlSb barrier layers were inserted. As the thickness of AlSb barriers(Lb)increased from 0.5 to 2 ML, the difference between the peak current density and the valley current density increased. This result indicates the crucial role of the extremely thin AlSb barrier layers that are responsible for the resonance level and move it up toward the GaSb valence-band edge with an increase inLb.©1997 American Institute of Physics.