Web Release Date: June 30,
Synthesis and Properties of Single-Crystal FeSi Nanowires
and
Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, and Lehrstuhl Angewandte Physik - Sensorik, BTU Cottbus, 03046 Cottbus, Germany
Received March 10, 2006
Revised June 2, 2006
Abstract:
We report for the first time the chemical synthesis of free-standing single-crystal nanowires (NWs) of FeSi, the only transition-metal Kondo
insulator and the host structure for ferromagnetic semiconductor FexCo1-xSi. Straight and smooth FeSi nanowires are produced on silicon
substrates covered with a thin layer of silicon oxide through the decomposition of the single-source organometallic precursor trans-Fe(SiCl3)2(CO)4 in a simple chemical vapor deposition process. Unlike typical vapor-liquid-solid (VLS) NW growth, FeSi NWs form without the addition
of metal catalysts, have no catalyst tips, and depend strongly on the surface employed. X-ray spectroscopy verifies the identity and the
room-temperature metallic nature of FeSi NWs. Room-temperature electrical transport measurements using NW devices show an average
resistivity of 210 
cm, similar to the value for bulk FeSi. Investigations into the low-temperature physical properties of the first one-dimensional Kondo insulator and the possible new NW growth mechanism are underway. This unique synthetic approach to FeSi NWs will be
generally applicable to many other transition-metal silicides.
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