Metal-semiconductor amorphous and nanoscale Ge-phase composites produced by rapid solidification and by devitrification of an amorphous matrix

In the current paper, we review our recent studies and present new data on Ge- and Si-based amorphous and composite alloys containing nanoscale semi-conductive Ge or Ge(Si) solid solution particles homogeneously distributed in a conductive amorphous matrix formed by rapid solidification or by devitrification of an amorphous single phase. Ge-rich alloys containing up to 70 at.% Ge were produced in Ge-Al-Cr-RE (RE, rare earth elements) systems, while Si-based amorphous alloys containing up to 60 at.% Si were produced in Si-Al-TM (TM, transition metals) systems by the melt-spinning technique. The samples are ribbons 10-100 μm thick. Nanocomposites in Si-Al-TM-Ge and some Ge-Al-Cr-RE alloys were produced directly by rapid solidification, while in the Ge ₅₅Mg ₃₅Y ₁₀ alloy they were produced by devitrification of the glassy phase on heating. The semiconductive nanoparticles exhibit homogeneous distribution, and their sizes vary from ∼5 nm to 20 nm. The structure, phase transformations, and properties of the samples are discussed.