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1006-R01-08

FABRICATION AND OPTICAL CHARACTERIZATION OF SILICON CARBIDE NANOFIBERS Saima N. Khan, Aurangzeb Khan, and Martin E. Kordesch Physics & Astronomy, Ohio University, Athens, OH, 45701 ABSTRACT Silicon Carbide (SiC) nanofibers were synthesized from SiC powder dispersed in polyethylene oxide (PEO) solution in Chloroform using the electrospinning technique. The as-spun fibers were then annealed at 1000 ˚C to 7 hours. The average diameter of the annealed fibers is 500 nm while the length of the annealed fibers is about 50 µm. The fibers were characterized using scanning electron microscope (SEM), X-ray diffraction (XRD) and Cathodoluminescence (CL). PL spectra from the annealed SiC fibers show a broad emission in the red-infrared spectral regime. The main peak is centered at 774 nm while the shoulder on the left is at 740 nm. INTRODUCTION Silicon carbide (SiC) holds an important position among the semiconducting ceramic materials because of its high breakdown electric field (3-5MV/cm, higher than silicon), high thermal conductivity (350-490 W m-1 K-1) and low mass density [1,2,3]. Nanostructures of SiC have attracted a great deal of attention for their tremendous potential in applications as reinforcements in the development of nano-composites [4]. Silicon carbide (SiC) nanofibers possess high mechanical strength and oxidation resistance at elevated temperature [5] and provide a perfect alternative for the development of metal matrix composites where carbon nanotubes can not be used since degradation can occur through the reaction of carbon with metals [6]. These composite materials are used to prepare equipment parts capable of operating in high temperature environments. In addition, electronic devices based on SiC nanostructures are capable of operating at high powers, high temperatures and high frequencies [7, 8]. Nanostructures of SiC are of great interest because of their broad range of potential applications such as field electron emitters, light emitters [9]. In particular, the nanofibers of SiC possess high aspect ratios, which make them suitable for applications as field emitters [10, 11, 12, 13]. Attempts have been made to synthesize SiC nanofibers via various methods such as chemical vapor deposition (CVD) [14], high power microwave plasma chemical vapor deposition [15], heat treating carbon nanotubes covered with Silicon [16] and from a precursor of two types of Polycarbosilanes (type-A and type-L) [17]. The procedures mentioned above however, either require sophisticated equipment or expensive carbon nanotubes or involve several preparation steps. Moreover, the SiC fibers thus obtained are only less than a 100 nm long. The synthesis of these fibers therefore remains a challenge and needs a great deal of attention In this paper we report for the first time (to the best of our knowledge) the synthesis of SiC nanofibers from a dispersion of SiC powder in polymer solution using the

electrospinning technique. Crystallization of SiC particles in these SiC/polymer fibers is achieved by sintering at tem