Silicon Carbide Nanowire Heterostructures Constructed from Released Iron Catalysis
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1058-JJ04-02
Silicon Carbide Nanowire Heterostructures Constructed from Released Iron Catalysis Zhenyu Liu1, Vesna Srot2, Peter A. van Aken2, Manfred Rühle2, and Judith C. Yang1 1 Department of Mechanical Engineering and Materials Science, University of Pittsburgh, 848 Benedum Hall, Pittsburgh, PA, 15261 2 Max-Planck-Institute for Metals Research, Heisenbergstrasse 3, Stuttgart, 70569, Germany ABSTRACT Herein, we present the capability of creating silicon carbide (SiC) nanowires and branched nanostructures via a released catalytic process. Core-shell structured carbonencapsulated iron nanoparticles were used as catalysts for SiC nanostructures formations by vapor-solid reaction. Various SiC nanostructures, including SiC nanocones, biaxial SiC-SiC composite nanowires, SiC-Fe-SiC junctions, Y, T branched SiC nanowires, and other complex heterostructures were observed from this process. It was demonstrated that the encapsulated iron could gradually migrate out of the carbon shell, and the released iron nanoparticles catalyzes the SiC nanostructures formation. Their morphologies and microstructures were investigated by different techniques, including scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM), and their formation mechanisms are proposed. INTRODUCTION One-dimensional (1D) nanostructures such as nanowires, nanorods, nanobelts, and nanotubes, have attractive electronic, mechanical, and optical properties and can be integrated into various nanodevices. [1-4] Thus, the synthesis of 1D nanostructures has become the focus of intensive research. Silicon carbide, an important group IV-IV semiconductor, possesses unique physical and electronic properties. Silicon carbide is a suitable material for electronic devices operating at high temperature, high power, and high frequency and in harsh environments. [5,6] One-dimensional SiC nanostructures are particularly interesting because micrometer-scale SiC whiskers are widely used as reinforcement materials and also nanoscale SiC shows higher strength and elasticity than SiC whiskers and bulk SiC. [7] Due to these unusual combination of properties, considerable effort has been made on the fabrication of SiC nanorods, nanoparticles, fibers and nanowires via different synthesis routes, such as carbon nanotube-converted reaction, carbon thermal reduction, chemical solution approach, and chemical vapor deposition. [8-16] Xu and coworkers reported the synthesis of needle-shaped SiC nanowire by catalyst-assisted thermal evaporation of commercial SiC particles at a high temperature of 1700oC. [17] Li and coworkers synthesized SiC nanorods, and Seeger et al. reported the synthesis of nano-scale SiC whiskers by an arc-discharge process. [18,19] Coaxial SiC-SiOX nanocable, biaxial SiC-SiOX, and SiCcarbon nanotube junction heterostructures have also been reported. [20] New functional nanoscale electronic devices require integration of the various nanoscale building blocks. Novel “bottom-up” approaches to produce well-defined heterostruc
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