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

Directional solidification of a Ge‐TiGe2 eutectic yields an array of aligned TiGe2 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 102–103 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 p‐type 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.