We propose and demonstrate a new GaSb/AlSb/GaSb/AlSb/InAs double-barrier interband tunneling diode with a peak-current density as high as 7.6 kA/cm 2 and a peak-to-valley current ratio of 5. In this device, the electrons in the InAs conduction band can resonantly tunnel through the AlSb/GaSb/AlSb double barrier into the GaSb valence band. By narrowing the GaSb well width from 65 to 30 Å, a drastic reduction of the tunneling current was found experimentally. This reduction is interpreted as evidences of the effect of the interband resonant tunneling process and the role of the light hole in the GaSb valence band. In addition, compared with the InAs/AlSb/GaSb/AlSb/InAs tunneling structure, a twice larger peak current density was obtained in the proposed structure which is attributed to a larger density of states of the GaSb light hole valence band compared with that of the InAs conduction band.