Ferromagnetic Mn-doped Si0.3Ge0.7 nanodots self-assembled on Si(100)

Densely packed epitaxial Mn-doped Si0.3Ge0.7 nanodots self-assembled on Si(100) have been obtained. Their structural properties were studied using reflection high-energy electron diffraction, energy dispersive x-ray diffraction, atomic force microscopy, extended x-ray absorption fine structure measurements and high-resolution transmission electron microscopy. Mn5Ge1Si2 crystallites embedded in Si0.3Ge0.7 were found. They exhibit a ferromagnetic behaviour with a Curie temperature of about 225 K.