Electronic structure of InAs/GaSb superlattice for the modelling of MWIR pin photodiode

• We present a 18-bands k.p method to simulate energies and wavefunctions.
• We study three different type of InAs/GaSb superlattices structures.
• Calculated bandgaps are in good agreement with results for symmetrical superlattice.
• We explain from model the difference of behaviour between the structures.
• We calculate intrinsic carrier concentration and effective mass.

An 18-band k.p formalism has been developed to determine the band structure and wavefunctions of InAs/GaSb type II superlattices (T2SL). Bandgap results are in good agreement with measurements for symetrical superlattices. Thus, we are able to calculate intrinsic properties of InAs/GaSb SL as the effective mass, the density of state and the free carrier concentration. Then we compare the modelled and measured electro-optical properties of three different SL structures with a different InAs to GaSb thickness ratio R per SL period, but having the same cut-off wavelength of 5 μm at 77 K.