SYNTHESIS AND CHARACTERIZATION OF CUBIC SILICON CARBIDE (beta-SiC) AND TRIGONAL SILICON NITRIDE (alpha-Si_3N_4) NANOWIRES

摘要

By varying the final heating temperature in the range 1050 deg C - 1300 deg C, cubic silicon carbide (beta-SiC) and/or trigonal silicon nitride (alpha-Si_3N_4) nanowires (NWs) were prepared by direct thermal treatment under nitrogen, of commercial silicon powder and graphite. Long and highly curved beta-SiC NWs were preferentially grown below 1200 deg C, while straight and short alpha-Si_3N_4 NWs were formed above 1300 deg C. Between these two temperatures, a mixture of both nanowires was obtained. The structure and chemical composition of these nanostructures have been investigated by SEM, HRTEM, EDX and EELS.