SiC nanowires and SiC/SiO2 core-shell structural nanowires were synthesized via a simple thermal evaporation of CoxSiy melts at the temperature of 1500?C. The morphologies and yields of those SiC nanowires can be tune...SiC nanowires and SiC/SiO2 core-shell structural nanowires were synthesized via a simple thermal evaporation of CoxSiy melts at the temperature of 1500?C. The morphologies and yields of those SiC nanowires can be tuned by altering the composition of CoxSiy. Nanowires obtained by thermal evaporation of Co Si are composed of SiC/SiO2 core-shell nanostructures with lengths up to several hundreds of micrometers, diameters of 4050 nm, and the thickness of amorphous SiO2 wrapping shell about 20 nm. SiC nanowires prepared by thermal evaporation of Co Si2 and Co2 Si melt are found to be hexagonal-prism-shaped nanorods, and the diameter of those nanorods is about 150 nm and the length is about 10 microns. All the SiC nanowires obtained possess [111] preferred growth direction with a high density stacking faults and twin defects. Taking into consideration the binary alloy diagram of Co Si and the participation of oxygen, we propose the vapor-solid growth mechanism of SiC nanowires and discuss the effect of the supersaturation of Si O on the morphology and yields of SiC nanowires.展开更多
YBa2Cu3Ox(YBCO) thin films grown on different substrates with and/or without Eu2CuO4(ECO) buffer layer were investigated by X-ray wide angle diffraction,reflection,diffuse scattering and topography.Theresults show tha...YBa2Cu3Ox(YBCO) thin films grown on different substrates with and/or without Eu2CuO4(ECO) buffer layer were investigated by X-ray wide angle diffraction,reflection,diffuse scattering and topography.Theresults show that for the yttria stabilized ZrO2(YSZ) substrate,the presence of an ECO buffer layer improves the crystalline quality of the YBCO film,while a negative effect is observed for the SrTiO3(STO) substrate.The lateral correlation length for a sample grown on a YSZ substrate with ECO buffer Layer is much greater than grown on an STO subetrate.The STO substrate used has mosaic structure.2001 Elsevier Science B.V.All rights reserved.展开更多
基金supported by the National Nature Science Foundation of the People’s Republic of China(Grant no.50902124)the National Basic Research Program of China(973 Program)(Grant no.2010CB933501)+1 种基金financial support from the Zhejiang Provincial Natural Science Foundation(Grant no.Y4090468)Science and Technology Department of Zhejiang Province(Grant no.2009F70046)
文摘SiC nanowires and SiC/SiO2 core-shell structural nanowires were synthesized via a simple thermal evaporation of CoxSiy melts at the temperature of 1500?C. The morphologies and yields of those SiC nanowires can be tuned by altering the composition of CoxSiy. Nanowires obtained by thermal evaporation of Co Si are composed of SiC/SiO2 core-shell nanostructures with lengths up to several hundreds of micrometers, diameters of 4050 nm, and the thickness of amorphous SiO2 wrapping shell about 20 nm. SiC nanowires prepared by thermal evaporation of Co Si2 and Co2 Si melt are found to be hexagonal-prism-shaped nanorods, and the diameter of those nanorods is about 150 nm and the length is about 10 microns. All the SiC nanowires obtained possess [111] preferred growth direction with a high density stacking faults and twin defects. Taking into consideration the binary alloy diagram of Co Si and the participation of oxygen, we propose the vapor-solid growth mechanism of SiC nanowires and discuss the effect of the supersaturation of Si O on the morphology and yields of SiC nanowires.
文摘YBa2Cu3Ox(YBCO) thin films grown on different substrates with and/or without Eu2CuO4(ECO) buffer layer were investigated by X-ray wide angle diffraction,reflection,diffuse scattering and topography.Theresults show that for the yttria stabilized ZrO2(YSZ) substrate,the presence of an ECO buffer layer improves the crystalline quality of the YBCO film,while a negative effect is observed for the SrTiO3(STO) substrate.The lateral correlation length for a sample grown on a YSZ substrate with ECO buffer Layer is much greater than grown on an STO subetrate.The STO substrate used has mosaic structure.2001 Elsevier Science B.V.All rights reserved.