InAs/InAsSb type 2 superlattices band parameters determination via magnetoabsorption and k.p modeling
Infrared cameras are used in a wide variety of applications, from military to civilian. Cryogenically cooled IR cameras based on photon detector arrays are many times more sensitive and faster than uncooled microbolometer thermal imagers.Ga free InAs/InAsSb type 2 superlattice (T2SL) based devices have been recently fabricated and they showed a first realization of MWIR (Mid Wave InfraRed) broadband detection up to 5mm. However the band parameters (band offsets, effect of strain, effective mass) of this material system have not been determined accurately, thus limiting the understanding and the prediction of the electronic properties of the devices. In this work we determined the relevant parameters via magnetoabsorption measurements performed on dedicated T2SL samples. Interband magneto optical transitions lead to an accurate mapping of the Landau levels. The Landau level energies have been calculated using an 8 bands k.p model and the comparison with the experimental data provided a clear description of the T2SL band structure at low temperatures.