ABSTRACT
Epitaxial layers of (GaMn)As have been grown successfully on GaAs substrates by metal-organic vapour phase epitaxy (MOVPE). Depending on the growth conditions clusters are found in these layers, which are responsible for the ferromagnetic coupling of these films also above room temperature. It is shown by high resolution transmission electron microscopy (HRTEM), electron diffraction (SAED) and energy-dispersive X-ray analysis (EDX) that the clusters are of the hexagonal NiAs structure and contain a significant amount of Ga. They grow heteroepitaxially within the GaAs:Mn film and the clusters as well as the matrix are free of defects.
