It was observed that the conduction‐band minimum of InAs is lower in energy than the valence‐band maximum of GaSb. This will cause the non‐rectification characteristic. Such unusual nonrectifying p‐n junction is the direct consequence of interpenetration between the GaSb valence band and the InAs conduction band, since the InAs‐GaSb superlattices can have a band gap smaller than that of either constituent materials. InAs‐GaSb superlattices have the modifiable band gap, but the absorption coefficient shall decrease rapidly when the period thickness is over 100 Å(d1=d2). It has a good spectral response in 3–5 μm region, but bad in 8–14 μm. The new proposal offered a normal incidence valence intersubband transition at ∼10μm. It is potential to fabricate the long wavelength devices.