Preparation of Highly Flexible SiC Nanowires by Fluidized Bed Chemical Vapor Deposition†

Abstract

High flexible SiC nanowires with diameters in the range of 10 to 50 nm and lengths of several hundred micrometers to several millimeters are synthesized using a novel catalyst-assisted fluidized bed chemical vapor deposition method. Methyltrichlorosilane (MTS) is used as source material and particles containing cobalt were used as catalyst. The fluidized bed is specially designed to form a perpendicular uneven temperature distribution. Suspended nanosized liquid catalyst droplets are produced at middle high temperature zone and SiC nanowires are formed in situ on the catalyst droplets then accumulated at the upper part of fluidized bed. The nanowires exhibit a single crystal feature with some stacking faults. Transmission electron microscopy (TEM) analysis verifies a growth direction along the <111> axis of the nanowires. A blue shift optical emission band at about 420 nm is detected using photoluminescence spectroscopy. From the high-resolution TEM investigation, a nanoscale smooth plane between the nanowire and the catalyst tip is observed and the two phases exhibit highly epitaxial growth interface. The growth process of the nanowires is discussed and a possible formation mechanism is proposed.