Strong ultraviolet and green photoluminescence from SiC/SiO2 core–shell nanowires

• SiC/SiO2 core–shell nanowires were synthesized on Si (100) substrate.
• An intensive sharp ultraviolet peak and an intensive broad green band are observed.
• Our results clarify the origin of luminescence in SiC/SiO2 core–shell nanowires.
• These nanowires have potential applications in integrated nanoelectronic devices.

SiC/SiO2 core–shell nanowires were synthesized on Si (100) substrate by the reaction of methane with silicon dioxide using iron as catalyst. Structural properties of the nanowires were characterized by Scanning electron microscopy, Transmission electron microscopy and X-ray diffraction. The light-emitting properties of nanowires were studied by photoluminescence spectroscopy. A sharp ultraviolet peak at 380 nm and an intensive broad green band with defined maximum peak at 505 nm were observed in spectra of as-grown nanowires. In addition, the emission intensity of ultraviolet peak decreased gradually until disappeared, but the green band emission intensity increased gradually when nanowires further annealed with different durations in oxygen and argon mixed gas atmosphere. The change of emission intensity could be attributed to different origins of photoluminescence peak: the ultraviolet peak originated from the oxygen-vacancy defects in the SiO2 shell and the green band that came from the SiC cores caused by quantum confinement effect.

Photoluminescence spectra of nanowires before and after annealed in oxygen and argon mixed gas atmosphere for 3 min, 5 min and 30 min, respectively.Figure optionsDownload as PowerPoint slide