Atomic intermixing and segregation at the interface of InAs/GaSb type II superlattices

To determine the interfacial atomic intermixing of the InAs/GaSb T2SL, an innovative and straightforward method based on TEM techniques is proposed to analysize and investigate the interface stoichiometry of the InAs/GaSb T2SL. Using this method, the chemical components of the interfaces in InAs/GaSb T2SL can be quantitatively determined by fitting with the sigmoidal function and Muraki's segregation model. It is found that the intermixing at the cationic and anionic sublattice is different, and the interface GaSb-on-InAs is slightly sharper than the InAs-on-GaSb interface. Furthermore, we identified segregation of Sb and In atoms and quantitatively measured their incorporation in the lattice. It is also found that the In and Sb segregations mainly occur at the GaSb-on-InAs and InAs-on-GaSb interfaces, respectively and the Sb segregation is larger than the In segregation in the as-grown InAs/GaSb superlattice because of the different atomic exchanges energy.