Normal-incidence intersubband and interband optical transitions in GaSb-InAs superlattices

Two interesting interband and intersubband optical transitions in the range of infrared wavelength were demonstrated using a type II GaSb-InAs superlattice structure. The interband transition results from the coupling between the wave functions of the first conduction and the first heavy-hole subband when Zn-doped GaSb p-type cap and buffer layers are used. On the other hand, the intersubband transition, which is a result of the strong mixing of the heavy-hole band and the light-hole band, was achieved by using InAs n-type cap and buffer layers. The wavelengths of interband and intersubband transitions is in the ranges of 3-5 μm and 8-14 μm, respectively. Consequently, there is a possibility of fabricating infrared photodetectors with the GaSb-InAs superlattices.