Intense photoluminescence (PL) was observed at room temperature from porous SiC samples prepared in electrochemical anodization from nano-crystalline SiC thin films grown on Si (100) substrates by hot filament chemical vapor deposition. Raman scattering spectroscopy and high-resolution transmission electron microscopy confirmed the nano-crystalline structure of the host films. For the porous samples formed under weaker anodization conditions, it was found that prolonged irradiation with ultraviolet (UV) light from a He-Cd laser (325nm, 10mW) can induce an enhanced new PL band and change the peak energy from 1.9eV to 2.1eV at room temperature. A defect model is suggested to explain the UV light induced PL change in porous SiC.

In this paper, our work is reported on heteroepitaxial monocrystalline SiC films deposited on single-crystalline (111) silicon by hot filament chemical vapor deposition (HFCVD) with a gas mixture of methane, silane and hydrogen at a low temperature of 780℃. The surface micrography and thickness of SiC films on Si (111) substrate were analyzed by scanning electron microscopy (SEM). The characteristics and crystallinity of the SiC film were examined by X-ray diffrac tometer (XRD), transmission electron microscopy (TEM) and auger electron spectrum (AES). The peaks of Si (111), SiC (111) and SiC (222) planes were observed on the X-ray diffraction spectrum, but not the peaks of the SiC (200) or SiC (220) planes. The diffraction pattern of TEM also indicates that the SiC films are single-crystalline structure. AES shows that the element ratio of silicon and carbon in the SiC film is 1:1.004. The preparation conditions were as follows: a filament temperature of 2100℃, substrate temperature of 780°C, hydrogen flow rate of 100 sccm, methane concentration of 8.0%, silane concentration of 1.0% and a reaction pressure of 150 Pa.

Nanocrystalline cubic silicon carbide (3C-SiC) films embedded in an amorphous SiC matrix were fabricated by the hot-filament chemical-vapor-deposition technique using methane and silane as reactance gases. High-resolution transmission electron micrographs clearly showed that these films contain naoncrystallites, with an average dimension of about 7 nm, embedded within an amorphous matrix: X-ray photoelectron spectroscopy, x-ray diffraction, infrared absorption, and Raman scattering studies revealed the nanocrystallites as having the structure of that of 3C-SiC. In contrast to 3C-SiC, where no photoluminescence could be observed at room temperature, strong visible emission with a peak energy of 2.2 eV could be seen from the nanocrystalline films at room temperature. The presence of nanocrystalline cubic SiC in these films is believed to result in a change in their energy-band structure, compared to that of 3C-SiC, which promotes radiative recombination of electron-hole pairs.

Intense wide-band photoluminescence (PL) with high stability to ultraviolet (UV) light irradiation has been observed in a wide temperature range from a polycrystalline SiC sintered from graphite and melt Si at high temperature over 1500

In this paper, we present a novel method to grow 3C-SiC crystal in a liquid-phase epitaxy-like manner, but without any substantial substrate. The starting material to be used in this method is the 3C-SiC-thin film deposited on Si substrate in a gas-phase heteroepitaxial technology. The free 3C-SiC film which remained of the molten Si substrate epitaxially grows up from the Si solution saturated by SiC in a highly purified graphite crucible heated by an inductive heater. XRD, XPS and Raman spectroscopy were used to characterize the samples. The only one peak with full width at half maximum (FWHM) of 0.2 at 20 = 35.65