Investigation of oval defects in (In)Ga(Al)As/GaAs heterostructures by spatially resolved photoluminescence and micro-cathodoluminescence

Oval defects, which are commonly found in epitaxial (In)Ga(Al)As heterostructures grown by molecular beam epitaxy (MBE) technique, are studied in this paper. The investigations of the morphology as well as the optical properties of defects were performed by scanning electron microscopy (SEM), cathodoluminescence (CL) and spatially resolved photoluminescence (SRPL). The conclusions are drawn as to the sources of defects, conditions of their appearance and their possible internal structure.