| Silicon carbide (SiC), a wide gap semiconductor, has attracted considerable research interest in recent years due to its potential applications in optoeletronic devices such as blue-green light emitting diodes (LED) and ultraviolet photodetectors. However, being indirect energy band gap semiconductor, crystalline SiC only exhibits weak blue PL peaks at 460nm at low temperature, and blue LED based on this material with a quantum efficiency of only about 1×10-4 and light emitting efficiency of only 1.4×10-4lm/W。To improve its light emitting efficiency, porous SiC has been fabricated and from which intense visible PL has been observed at room temperature. However, the low stability and reproducibility of porous SiC as well as incompatibility with Si IC technology greatly limit its application in optoelectronic devices. Recently, nano-composite thin film materials have been extensively studied because they have both advantages of common composite materials and modern nanometer materials. Especially, semiconductor nanocrystals embedded in other matrixs have a great potential for the development of optoelectronic devices. This is due to their striking optical and optoelectronic properties, which strongly differ from those of the corresponding bulk materials. In principle, this is related to the existence of quantum confinement effects of excitons in the nanoparticles, which lead to a drastic bandgap opening and enhancement of radiative recombination rates. Besides, the stability and compatibility with Si IC technology is much better than porous SiC, becoming the focus of current reseach. Therefore, the fabrication of SiC nanoclusters embedded in SiO2 matrix is of great significance in the development of optoelectronics and large scale optoelectronics integrated circuit (OEIC). The silicon carbide/silicon oxide (SiC/SiO2) nano-composite thin films with embedded structures were prepared on n-type Si(111) substrates by radio frequency(RF) magnetron co-sputtering and subsequent high temperature annealing with a SiC/SiO2 composite target. The structure, morphology and photoluminescent properties of the films was determined by X-ray diffraction (XRD) ,Fourier transform infrared transmission spectroscopy (FTIR),X-ray photoelectron spectroscopy (XPS),Scanning electronic microscopy (SEM) and Photoluminescence (PL). The results show that the as-deposited film is mainly amorphous phase and crystallization takes place in the composite films and a little quantity of α-SiC with small granule sizes is formed after annealing at 900℃for 30min. With the further increasing annealing temperature, crystallization quality becomes much better and a part of α-SiC changes intoβ-SiC, which may nucleate into SiC nanoclusters embedded in SiO2 matrix. SiC nanocrystals are dispersed in the SiO2 matrix. Excited by 280nm light at room temperature, the films were found strong emission peaks at 365nm (ultraviolet band), 458nm and 490nm (blue bands). It was found that the PL intensity increased with the increasing annealing temperature. The origin of the PL spectra was attributed into the Si-O related defects such as –O-Si-C-O, -O-Si-O-and neutral oxygen vacancy were formed mainly at the interface between SiC nanoclusters and the SiO2 matrix. These defects are believed to be luminescence centers. With the increase of annealing temperature, crystallization becomes much better, resulting in the increase of the number and the total surface area of SiC nanoclusters. Moreover, the local strain induced due to crystallization greatly facilitates the formation of more Si-O related luminescence centers, which results in the increase of the rate of radiative recombination. Therefore, PL intensity increased greatly with the increase of annealingtemperature. Further studies about the mechanism of PL are still in progress. Zinc oxide (ZnO), a direct and wide band-gap (3.37eV) semiconductor with large exciton binding energy (60meV), has been considered as a promising natural candidate for studies in modern nanoelectronics and photonics. Catalytic reaction growth based on vapor-liquid-solid (VLS) mechanism, Templet-confined growth, MOVPE growth and Self-assembly growth have been becoming dominating classical techniques to grow low-dimensional ZnO nanostructures. With peculiar structure and physical property, the preparation of one-dimensional ZnO nano-structure not only provides invaluable research object for fundamentally physical studies such as exploration of small size quantum confinement effect and molecule-size level nanometer optoelectronics devices, but also promises immense application prospect and economic benefit, which would bring about revolutionary transform to traditional material, microelectronic and medical fields as well as influences on people's routine life. The novel fabrication methods of one-dimensional ZnO nano-structure are still to be explored. It is of great significance to prepare ZnO nano-structure materials with new shape. A simple and novel method is discussed in this paper to prepare large quantities of one-dimensional ZnO nanowires. Zn/SiO2 composite thin films were deposited on Si (111) substrates with radio frequency magnetron co-sputtering, then annealed at 650℃for different time. Metal zinc vapor separating out from SiO2 matrix reacted with oxygen and large quantities of one-dimensional ZnO nanowires were formed on the surface when the annealing time lasted 40min. The diameters of ZnO nanowires ranged between 40 and 80nm, with lengths as long as several micrometers, whilst porous SiO2 networks were formed under nano-ZnO layers. The number of ZnO nanowires reduced gradually with the increase of annealing time. Under...
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