Preparation and characterization of yellow-green fluorescence emitting SiC-encapsulated graphite

SiC-encapsulated graphite was prepared by carbonization of a mixture of expanded graphite and silica sol at 1 300℃ for 6 h, heat treatment in air at 700 ℃ for 4 h to remove unreacted surface carbon and HCl-HF etching to remove silica. XRD, TGA, TEM and SEM were used to characterize the samples. Results indicated that the fluorescence emission of the SiC-encapsulated graphite shifts from blue to yellow-green light compared to pure SiC. This might be caused by a built-in potential near the junction between graphite and SiC, which makes the energy of the photogenerated electron released while returning to ground state lower than that of pure SiC.