Optimization of GaSb buffer layers on silicon substrates for optoelectronic applications

In this work we investigate the application and optimization of GaSb buffers on Silicon for improved device performance in the mid-wave infrared (MWIR). In particular, we examine the nucleation process of AlSb to create a template for growth of the GaSb buffer, as well as the use of defect filtering layers for reducing residual threading dislocations in the buffer layer. The location of the defect filtering layer plays a role in its effectiveness. Threading dislocation densities as low as mid-10⁷ defects/cm² have been achieved. This study includes analysis from photoluminescence spectroscopy, transmission electron microscopy, temperature-dependent x-ray diffraction studies, and x-ray diffraction reciprocal space mapping.