ZnO crystals were grown by CVT method in closed quartz tube under seeded condition. Carbon was used as a transport agent to enhance the chemical transport of ZnO in the growth process. ZnO single crystals were grown b...ZnO crystals were grown by CVT method in closed quartz tube under seeded condition. Carbon was used as a transport agent to enhance the chemical transport of ZnO in the growth process. ZnO single crystals were grown by using GaN/sapphire and GaN/Si wafer as seeds. The property and crystal quality of the ZnO single crystals was studied by photoluminescence spectroscopy and X-ray diffraction technique.展开更多
Zinc alloy coating attracted much attention due to its high anti-corrosive properties.Particularly,zinc alloy coatings containing magnesium was considered a promising metallic alloy due to a remarkable improvement of ...Zinc alloy coating attracted much attention due to its high anti-corrosive properties.Particularly,zinc alloy coatings containing magnesium was considered a promising metallic alloy due to a remarkable improvement of corrosion resistance.The proper magnesium content for Zn-Mg alloy coatings was studied.The samples were prepared using thermal evaporation method.The influence of Zn-Mg alloy coating on corrosion resistance was evaluated using immersion test,potentiodynamic test,and galvanic test in 3% NaCl solution at room temperature.The results show that the corrosion resistance of Zn-Mg alloy coatings is strongly dependent on magnesium content.Corrosion potential decreases with increasing magnesium content,whereas current density increases up to 15% magnesium content,and passivity region was found only in Zn-Mg coatings.展开更多
1 IntroductionIn the very recent years, low-dimensional nanomaterials have attracted a great interest in nanoscience and nanotechnology due to their exciting application in electronics[1], optoelectronics[2] and mecha...1 IntroductionIn the very recent years, low-dimensional nanomaterials have attracted a great interest in nanoscience and nanotechnology due to their exciting application in electronics[1], optoelectronics[2] and mechanics[3] in nanoscale. Compared to bulk materials,展开更多
ZnO hexagonal prism crystals were synthesized from ZnO powders by microwave heating in a short time （within 20 min） without any metal catalyst or transport agent. Zinc oxide raw materials were made by evaporating fr...ZnO hexagonal prism crystals were synthesized from ZnO powders by microwave heating in a short time （within 20 min） without any metal catalyst or transport agent. Zinc oxide raw materials were made by evaporating from the high-temperature zone in an enclosure atmosphere and crystals were grown on the self-source substrate. The inherent asymmetry in microwave heating provides the temperature gradient for crystal growth. Substrate and temperature distribution in the oven show significant effects on the growth of the ZnO crystal. The morphologies demonstrate that these samples are pure hexagonal prism crystals with maximum 80 lain in diameter and 600 lure in length, which possess a well faceted end and side surface. X-ray diffraction （XRD） reveals that these samples are pure crystals. The photoluminescence （PL） exhibits strong ultraviolet emission at room temperature, indicating potential applications for short-wave light-emitting photonic devices.展开更多
A vapor deposition method was applied to synthesize zinc oxide（ZnO） nanowires and nanorods with diameter from 40 nm to 500 nm, length from 1 μm to 70 μm by adjusting the flow rate of argon, oxygen and the pressure...A vapor deposition method was applied to synthesize zinc oxide（ZnO） nanowires and nanorods with diameter from 40 nm to 500 nm, length from 1 μm to 70 μm by adjusting the flow rate of argon, oxygen and the pressure during growth. Results of scanning electron microscopy（SEM） and high resolution transmission electron microscopy（TEM） proved the hexagonal wurtzite structure of the synthesized ZnO nanowires or nanorods, which grow along the 0001 direction. The results show that the growth conditions strongly impact the morphology, growth rate and optical properties of the ZnO nanostructures.The ZnO nanowires with small diameters tend to show stronger ultraviolet（UV） light emission from the electron-hole recombination near band edge in photoluminescence（PL）, while those with larger diameters tend to exhibit PL spectra dominated by the broad green light emission due to the defects.展开更多
文摘ZnO crystals were grown by CVT method in closed quartz tube under seeded condition. Carbon was used as a transport agent to enhance the chemical transport of ZnO in the growth process. ZnO single crystals were grown by using GaN/sapphire and GaN/Si wafer as seeds. The property and crystal quality of the ZnO single crystals was studied by photoluminescence spectroscopy and X-ray diffraction technique.
基金supported by the Smart Coating Steel Development Center,World Premier Materials (WPM) Program of the Ministry of Knowledge Economy of Korea and Korea Maritime University
文摘Zinc alloy coating attracted much attention due to its high anti-corrosive properties.Particularly,zinc alloy coatings containing magnesium was considered a promising metallic alloy due to a remarkable improvement of corrosion resistance.The proper magnesium content for Zn-Mg alloy coatings was studied.The samples were prepared using thermal evaporation method.The influence of Zn-Mg alloy coating on corrosion resistance was evaluated using immersion test,potentiodynamic test,and galvanic test in 3% NaCl solution at room temperature.The results show that the corrosion resistance of Zn-Mg alloy coatings is strongly dependent on magnesium content.Corrosion potential decreases with increasing magnesium content,whereas current density increases up to 15% magnesium content,and passivity region was found only in Zn-Mg coatings.
基金Supported by the National Natural Science Foundation of China(Nos.20827004, 20873050, 20921003, 20973074, 21073072)the "111" Project of China(No.B06009)+1 种基金the Research Fund for the Doctoral Program of Higher Education of China (No.20100061120087)the Postdoctoral Science Foundation of China(No.20090451146)
文摘1 IntroductionIn the very recent years, low-dimensional nanomaterials have attracted a great interest in nanoscience and nanotechnology due to their exciting application in electronics[1], optoelectronics[2] and mechanics[3] in nanoscale. Compared to bulk materials,
基金the National Natural Science Foundation of China (No. 50472043)the Program for New Century Excellent Talents in Universities (No. NCET-06-0658)
文摘ZnO hexagonal prism crystals were synthesized from ZnO powders by microwave heating in a short time （within 20 min） without any metal catalyst or transport agent. Zinc oxide raw materials were made by evaporating from the high-temperature zone in an enclosure atmosphere and crystals were grown on the self-source substrate. The inherent asymmetry in microwave heating provides the temperature gradient for crystal growth. Substrate and temperature distribution in the oven show significant effects on the growth of the ZnO crystal. The morphologies demonstrate that these samples are pure hexagonal prism crystals with maximum 80 lain in diameter and 600 lure in length, which possess a well faceted end and side surface. X-ray diffraction （XRD） reveals that these samples are pure crystals. The photoluminescence （PL） exhibits strong ultraviolet emission at room temperature, indicating potential applications for short-wave light-emitting photonic devices.
基金financially supported by the National Natural Science Foundation of China (No. 61428403 and 51422106)
文摘A vapor deposition method was applied to synthesize zinc oxide（ZnO） nanowires and nanorods with diameter from 40 nm to 500 nm, length from 1 μm to 70 μm by adjusting the flow rate of argon, oxygen and the pressure during growth. Results of scanning electron microscopy（SEM） and high resolution transmission electron microscopy（TEM） proved the hexagonal wurtzite structure of the synthesized ZnO nanowires or nanorods, which grow along the 0001 direction. The results show that the growth conditions strongly impact the morphology, growth rate and optical properties of the ZnO nanostructures.The ZnO nanowires with small diameters tend to show stronger ultraviolet（UV） light emission from the electron-hole recombination near band edge in photoluminescence（PL）, while those with larger diameters tend to exhibit PL spectra dominated by the broad green light emission due to the defects.
