InAs/GaSb/AlSb composite quantum well structure preparation with help of reflectance anisotropy spectroscopy

Mostly the structures were prepared by MBE, since preparing heterostructures of this materials system by MOVPE presents several challenges. We have successfully prepared by MOVPE structures with broken gap InAs/GaSb composite quantum wells surrounded by AlSb barriers on InAs and GaSb substrates. The whole process of structure preparation was optimized with help of in situ LayTec Epiras measurements. Suitable interfaces, switching sequences, growth rates and suitable precursors for the growth of the structure are discussed. The quality of the structure was checked by electron paramagnetic resonance for differently oriented magnetic field up to 14 kOe at temperatures from 2.7K to 20 K. Intense Shubnikov de Haas oscillations appeared at low temperatures and helped us characterize the properties of the structure.