Growth of lattice matched InAs/AlSb superlattices by molecular beam epitaxy br

The InAs/GaSb superlattices (SPLs) is an important component of quantum cascade laser (QCL) andinterband cascade laser (ICL). In particular, the upper and lower SPL waveguide layers of the ICL arealternately grown from a large number of ultra-film epitaxial layers (nm) by molecular beam epitaxy(MBE).Subtle lattice mismatch may directly lead to the deterioration of material crystal quality, and the change ofthicknessand the composition of each layer will strongly affect the structural performance of device material.The optimal growth temperature of InAs/GaSb SPLs is about 420 degrees C. By growing GaSb/AlSb and InAs/GaSbSPL both with 40 short periods under the substrate rotating, the thickness of GaSb layer and AlSb layer are5.448 nm and 3.921 nm, and the thickness of InAs layer and GaSb layer are 8.998 nm and 13.77 nm,respectively. The error is within about 10%, and the optimal growth conditions of InAs/AlSb SPLs areobtained. A lattice matched 40-period InAs/AlSb superlattice waveguide layer is grown on GaSb substrate. Theinfluence of drifting As injection on the average lattice constant of InAs/AlSb superlattice is fully considered.Under the condition of fixed SOAK time of 3 s, the As pressure is changed to 1.7 x 10-6 mbar to adjust theaverage lattice constants of the superlattices and achieve their matching with the GaSb substrate lattice. Theexperimental results show that the 0 order satellite peak of the SPL coincides with the peak of the GaSbsubstrate, and has a perfect lattice matching, and that the sharp second order satellite peak and the periodicstructure good repeatability also indicate that the superlattice material has the excellent structural quality ofthe SPLs structure