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 semiconductive 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 Ge55Mg35Y10 alloy they were produced by devitrification of the glassy phase on heating. The semiconductive nanoparticles exhibit homogeneous distribution, and their sizes vary from ∼7 nm to 20 nm. The structure, phase transformations, and properties of the samples are discussed.