Study of Blue Emission from Nano-SiC Powders During Rapid Thermal Annealing

Nanometric SiC powder was prepared by chemical vapor deposition at 1100°C, and samples were subsequently treated by rapid thermal annealing at 600-1100°C. The intensities of the blue photoluminescence were then measured a t room temperature. The peak intensity at 2.56 eV (484 nm) rises with annealing temperature, reaching a value about 9.2 times as high at 800°C, then drops very quickly at 900°C. Based on the results of x-ray diffraction, infrared spectroscopy, x-ray photoelectron spectroscopy and transmission electron microscopy, we conclude that the amounts of the twofold coordinated Si on the surface of the nanometric SiC particles play an important role in the photoluminescence intensity.