Dimensionality can play an important role in determining the properties of materials. In the case of thermoelectric materials, it has been proposed that one-dimensional quantum wires, or nanowires, and two-dimensional superlattices could exhibit substantially higher efficiencies compared to the corresponding bulk, three-dimensional solids. To explore such predictions we have initiated a program directed towards the controlled growth of nanowires, and herein, we report the synthesis of single crystal Bi_2Te_3 and PbTe nanowires by a pulsed laser ablation method. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) show that Bi_2Te_3 wires 80 nm to 200 nm in diameter and lengths exceeding 10 microns, and PbTe wires 25 nm to 60 nm in diameter and lengths to 2 microns can be readily produced by the laser ablation method. High-resolution TEM and electron diffraction show that Bi_2Te_3 nanowires are single crystals with wire axes along the <110> crystal direction. TEM and electron diffraction measurements also show that the PbTe nanowires are single crystals with a <100> growth axis. The transport properties of these new nanowire materials will be discussed.
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