Depletion zones surrounding aligned, cylindrical, metal‐semiconductor junctions formed during the directional solidification of a eutectic mixture are shown to influence the transport properties of the composite. Hall‐effect and direct depletion zone width measurements made using the electron beam induced current technique of the scanning electron microscope have demonstrated that a relatively small total volume fraction (∼10) of depleted material can lead to a significant increase in resistivity. The sensitivity of the resistivity of the composite to the depleted zone volume is attributed to a cellular distribution of the TaSi2rods which causes substantial current streamlining. An analysis of the dopant segregation that occurs in the Si matrix of the composite boule during solidification supports the depletion zone limited transport model. The dependence of the resistivity on the depleted zone volume fraction of the composite indicates that the switching action in this novel material is achievable by increasing the volume fraction of depleted material between a source and drain contact.
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