Migration characterizations of Ga and In adatoms on the dielectric surface in selective metal organic vapor phase epitaxy （MOVPE） were investigated. In the typical MOVPE environment, the selectivity of growth is pre...Migration characterizations of Ga and In adatoms on the dielectric surface in selective metal organic vapor phase epitaxy （MOVPE） were investigated. In the typical MOVPE environment, the selectivity of growth is preserved for GaN, and the growth rate of GaN micro-pyramids is sensitive to the period of the patterned SiO2 mask. A surface migration induced model was adopted to figure out the effective migration length of Ga adatoms on the dielectric surface. Different from the growth of GaN, the selective area growth of InGaN on the patterned template would induce the deposition of InGaN polycrystalline particles on the patterned Si02 mask with a long period. It was demonstrated with a scanning electron microscope and energy dispersive spectroscopy that the In adatoms exhibit a shorter migration length on the dielectric surface.展开更多
Ga N micro-pyramids with AlGaN capping layer are grown by selective metal–organic–vapor phase epitaxy（MOVPE）. Compared with bare Ga N micro-pyramids, AlGaN/Ga N micro-pyramids show wrinkling morphologies at the bo...Ga N micro-pyramids with AlGaN capping layer are grown by selective metal–organic–vapor phase epitaxy（MOVPE）. Compared with bare Ga N micro-pyramids, AlGaN/Ga N micro-pyramids show wrinkling morphologies at the bottom of the structure. The formation of those special morphologies is associated with the spontaneously formed AlGaN polycrystalline particles on the dielectric mask, owing to the much higher bond energy of Al–N than that of Ga–N. When the sizes of the polycrystalline particles are larger than 50 nm, the uniform source supply behavior is disturbed, thereby leading to unsymmetrical surface morphology. Analysis reveals that the scale of surface wrinkling is related to the migration length of Ga adatoms along the AlGaN {1ī01} facet. The migration properties of Al and Ga further affect the distribution of Al composition along the sidewalls, characterized by the μ-PL measurement.展开更多
Non-polar a-plane （1120） GaN films have been grown on r-plane （1102） sapphire substrates by metal organic chemical vapour deposition. The influences of V/III ratio on the species diffusion anisotropy of a-plane Ga...Non-polar a-plane （1120） GaN films have been grown on r-plane （1102） sapphire substrates by metal organic chemical vapour deposition. The influences of V/III ratio on the species diffusion anisotropy of a-plane GaN films were investigated by scanning electron microscopy, cathodoluminescence and high-resolution x-ray diffraction measurements. The anisotropy of a-plane GaN films may result from the different migration length of adatoms along two in-plane directions. V/III ratio has an effect on the growth rates of different facets and crystal quality. The stripe feature morphology was obviously observed in the film with a high V/III ratio because of the slow growth rate along the [1100] direction. When the V/III ratio increased from 1000 to 6000, the in-plane crystal quality anisotropy was decreased due to the weakened predominance in migration length of gallium adatoms.展开更多
Comparing fat content with physiological status can throw light on the reproduction and feeding behavior of the fish. The biological data of 586 bigeye tuna were collected from the longline fishery in the waters of We...Comparing fat content with physiological status can throw light on the reproduction and feeding behavior of the fish. The biological data of 586 bigeye tuna were collected from the longline fishery in the waters of Western Central Indian Ocean from November, 2012 to March, 2013. The spatial or temporal distribution of the fat content, and the relationships of fat content with gender, round weight, gonadal maturity and fork length were analyzed. A generalized additive model(GAM) was used to analyze the relationships between fat content and fork length(FL), gonadosomatic index(GSI), condition factor(K), and somatic index(SI). Results showed that: 1) the fat content of bigeye tuna was in the range of 3.1%–27.1% with the average 12.8%; 2) there were no significant geographical differences of average fat content(P > 0.05) among 1? squares in general; 3) there were no significant differences(P > 0.05) of the fat content for different genders, months, or gonad maturity stages; 4) there was an extremely significant correlation(P = 0.000) between fat content and FL and GSI. There was no significant correlation(P = 0.051) between fat content and K. There was a significant correlation(P = 0.003) between fat content and SI. The results of this study suggest that the fat content of the matured fish was relatively stable. The survey area was in a spawning region, and the survey period was the spawning season for bigeye tuna.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.61274039 and 51177175)the National Basic Research Program of China(Grant No.2011CB301903)+5 种基金the Ph.D.Programs Foundation of Ministry of Education of China(Grant No.20110171110021)the International Sci.&Tech.Collaboration Program of China(Grant No.2012DFG52260)the International Sci.&Tech.Collaboration Program of Guangdong Province,China(Grant No.2013B051000041)the Science and Technology Plan of Guangdong Province,China(Grant No.2013B010401013)the National High Technology Research and Development Program of China(Grant No.2014AA032606)the Opened Fund of the State Key Laboratory on Integrated Optoelectronics,China(Grant No.IOSKL2014KF17)
文摘Migration characterizations of Ga and In adatoms on the dielectric surface in selective metal organic vapor phase epitaxy （MOVPE） were investigated. In the typical MOVPE environment, the selectivity of growth is preserved for GaN, and the growth rate of GaN micro-pyramids is sensitive to the period of the patterned SiO2 mask. A surface migration induced model was adopted to figure out the effective migration length of Ga adatoms on the dielectric surface. Different from the growth of GaN, the selective area growth of InGaN on the patterned template would induce the deposition of InGaN polycrystalline particles on the patterned Si02 mask with a long period. It was demonstrated with a scanning electron microscope and energy dispersive spectroscopy that the In adatoms exhibit a shorter migration length on the dielectric surface.
基金supported by the National Natural Science Foundation of China(Grant Nos.61274039 and 61574173)the National Key Research and Development Program,China(Grant No.2016YFB0400105)+9 种基金the International Science and Technology Collaboration Program of Guangdong Province,China(Grant No.2013B051000041)the International Science and Technology Collaboration Program of Guangzhou City,China(Grant No.2016201604030055)the National High Technology Research and Development Program of China(Grant No.2014AA032606)Guangdong Provincial Natural Science Foundation,China(Grant No.2015A030312011)the Science&Technology Plan of Guangdong Province,China(Grant Nos.2015B090903062,2015B010132007,and2015B010129010)the Science and Technology Plan of Guangzhou,China(Grant No.201508010048)the Science and Technology Plan of Foshan,China(Grant No.201603130003)Guangdong–Hong Kong Joint Innovation Project of Guangdong Province,China(Grant No.2014B050505009)the Opened Fund of the State Key Laboratory on Integrated Optoelectronics(Grant No.IOSKL2014KF17)the Zhuhai Key Technology Laboratory of Wide Bandgap Semiconductor Power Electronics,Sun Yat-sen University(Grant No.20167612042080001)
文摘Ga N micro-pyramids with AlGaN capping layer are grown by selective metal–organic–vapor phase epitaxy（MOVPE）. Compared with bare Ga N micro-pyramids, AlGaN/Ga N micro-pyramids show wrinkling morphologies at the bottom of the structure. The formation of those special morphologies is associated with the spontaneously formed AlGaN polycrystalline particles on the dielectric mask, owing to the much higher bond energy of Al–N than that of Ga–N. When the sizes of the polycrystalline particles are larger than 50 nm, the uniform source supply behavior is disturbed, thereby leading to unsymmetrical surface morphology. Analysis reveals that the scale of surface wrinkling is related to the migration length of Ga adatoms along the AlGaN {1ī01} facet. The migration properties of Al and Ga further affect the distribution of Al composition along the sidewalls, characterized by the μ-PL measurement.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 60676032, 60577030 and 60476028)the National Basic Research Program of China (Grant No. 2007CB307004)the National Science Foundation for Post-doctoral Scientists of China (Grant No. 20060400018)
文摘Non-polar a-plane （1120） GaN films have been grown on r-plane （1102） sapphire substrates by metal organic chemical vapour deposition. The influences of V/III ratio on the species diffusion anisotropy of a-plane GaN films were investigated by scanning electron microscopy, cathodoluminescence and high-resolution x-ray diffraction measurements. The anisotropy of a-plane GaN films may result from the different migration length of adatoms along two in-plane directions. V/III ratio has an effect on the growth rates of different facets and crystal quality. The stripe feature morphology was obviously observed in the film with a high V/III ratio because of the slow growth rate along the [1100] direction. When the V/III ratio increased from 1000 to 6000, the in-plane crystal quality anisotropy was decreased due to the weakened predominance in migration length of gallium adatoms.
基金supported by the National High Technology Research and Development Program of China (863 program, No. 2012 AA092302)The Specialized Research Fund for the Doctoral Program of Higher Educationn (No. 20113104 110004)+3 种基金Shanghai Municipal Education Commission Innovation Project (No. 12ZZ168)Key Laboratory of Sustainable Exploitation of Oceanic Fisheries Resources (Shanghai Ocean University),Ministry of Education (No. A102091505037)Special funding for the development of science and technology of Shanghai Ocean University (No. A2020915200002)the Youth Scholars of Shanghai Higher Education Institutions (No. A1203514001014)
文摘Comparing fat content with physiological status can throw light on the reproduction and feeding behavior of the fish. The biological data of 586 bigeye tuna were collected from the longline fishery in the waters of Western Central Indian Ocean from November, 2012 to March, 2013. The spatial or temporal distribution of the fat content, and the relationships of fat content with gender, round weight, gonadal maturity and fork length were analyzed. A generalized additive model(GAM) was used to analyze the relationships between fat content and fork length(FL), gonadosomatic index(GSI), condition factor(K), and somatic index(SI). Results showed that: 1) the fat content of bigeye tuna was in the range of 3.1%–27.1% with the average 12.8%; 2) there were no significant geographical differences of average fat content(P > 0.05) among 1? squares in general; 3) there were no significant differences(P > 0.05) of the fat content for different genders, months, or gonad maturity stages; 4) there was an extremely significant correlation(P = 0.000) between fat content and FL and GSI. There was no significant correlation(P = 0.051) between fat content and K. There was a significant correlation(P = 0.003) between fat content and SI. The results of this study suggest that the fat content of the matured fish was relatively stable. The survey area was in a spawning region, and the survey period was the spawning season for bigeye tuna.
