Preparation and electrical properties of a directionally solidified Ge-TiGe2 eutectic

Abstract

Magnetic and metallurgical properties of directionally solidified eutectic Bi/MnBi composites: The effects of annealingDirectional solidification ofa Ge-TiGe 2 eutectic yields an array of aligned TiGe 2 fibers in a Ge matrix. These aligned metallic fibers result in a highly anisotropic material such that the ratio of the resistivities perpendicular and parallel to the rods is typically 10 2 _10 3 at room temperature and even larger at low temperatures. The resistivity of these semiconductor based eutectic composites is examined as a function of the type and concentration of donors. A significant distinction in the resistivity perpendicular to the rods is observed between composites with a ptype and n-type Ge matrix. This difference is analyzed in terms of the depletion layers at the metal-semiconductor junction, as well as the high density of crystalline defects in the Ge created by the two phase solidification and cooling stresses.