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Microstructure and performance of Al-si alloy with high si content by high temperature diffusion treatment

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Transactions of Nonferrous Metals Society of China 2010年第11期20卷 2134-2138页

作者：修子扬陈国钦王晓峰武高辉刘艳梅杨文澍 School of Material Science and Engineering Harb in Institute of Technology

The Al-si alloy with high si content was prepared by pressure infiltration.Microstructure observation shows that three-dimensional structure(3D-structure) is obtained from irregular sharp si particles via high temperature diffusion treatment(HTDT).Flat si-Al interfaces transform to smooth curves,and si phases precipitate in Al and si-Al interface.The bonding of si-Al interface is improved by HTDT,which improves the mechanical performance of Al-si alloy.The bending strength of 3D-Al-si alloy increases by 6% compared with that of Al-si alloy,but the elastic modulus changes a little.The coefficient of thermal expansion(CTE) of the 3D-Al-si alloy is 7.7×10-6/°C from 20 °C to 100 °C,which decreases by 7% compared with that of Al-si alloy.However,HTDT has little effect on the thermal conductivity of Al-si alloy.

关键词：合金制备高硅含量扩散处理力学性能 si 微观结构高温铝硅合金

Temperature-Dependent Photoluminescence from GaN/si Nanoporous Pillar Array

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Chinese Physics Letters 2015年第5期32卷 142-145页

作者：王小波李勇闫玲玲李新建 Department of Physics and Laboratory of Material Physics Zhengzhou University Zhengzhou 450052 ollege of Physics and Electrical Engineering Anyang Normal University Anyang 455000 Department of Physics and Solar Energy Research Center Pingdingshan University Pingdingshan 467000 College of Physics and Chemistry Henan Polytechnic University Jiaozuo 454000

A GaN/si nanoheterostructure is prepared by growing wurtzite GaN on a silicon nanoporous pillar array （si-NPA） with a chemical vapor deposition method. The temperature evolution of the photoluminescence （PL） of GaN/si- NPA is measured and the PL mechanism is analyzed. It is found that the PL spectrum is basically composed of two narrow ultraviolet peaks and a broad blue peak, corresponding to the near band-edge emission of GaN and its phonon replicas, and the emission from si-NPA. No GaN defect-related PL is observed in the as-prepared GaN/si-NPA. Our experiments prove that si-NPA might be an ideal substrate for preparing high-quality si-based GaN nanomaterials or nanodeviees.

关键词： GaN Temperature-Dependent Photoluminescence from GaN/si Nanoporous Pillar Array NPA si

Hierarchically 3D structured milled lamellar MoS2/nano-silicon@carbon hybrid with medium capacity and long cycling sustainability as anodes for lithium-ion batteries

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Journal of Materials Science & Technology 2019年第9期35卷 1840-1850页

作者： Peng Zhang Qiang Rua Honglin Yan Xianhua Hou Fuming Chen Shejun Hu Lingzhi Zhao Guangdong Engineering Technology Research Center o f Efficient Green Energy and Environmental Protection Materials South China Normal University Guangzhou 510006China Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials School of Physics and Telecommunication EngineeringSouth China Normal UniversityGuangzhou 510006China Engineering Research Center of Materials and Technology for Electrochemical Energy Storage (Ministry of Education) Guangzhou 510006China Institute of Optoelectronic Materials and Technology South China Normal UniversityGuangzhou 510631China

A hierarchically 3D structured milled lamellar MoS2/nano-siIicon@carbon hybrid with medium capacity and long-term lifespan is designed by a green and scalable approach using ball milling process and spraydrying/ pyrolysis routes. The microspheres consist of low-content nano-silicon (20 wt%), milled lamellar M0S2 sheets and porous carbon skeletons. A mixture of silicon nanoparticles and M0S2 flakes serves as an inner core, while porous carbon pyrolyzed from petroleum pitch acts as a protective shell. The particular architecture affords robust mechanical support, abundant buffering space and enhanced electrical conductivity, thus effectively accommodating drastic volume variation during repetitive Li+ intercalation/ extraction. The si/MoS2@C hybrid delivers a high initial discharge specific capacity of 1257.8 mA hg^-1 and exhibits a reversible capacity of 767.52 m A hg^-1 at a current density 100 mA g'1 after 250 cycles. Most impressively, the electrode depicts a superior long-cycling durability with a discharge capacity of 537.6 mA hg^-1 even after 1200 cycles at a current density of 500 m A g^-1. Meanwhile, the hybrid also shows excellent rate performance such as 388.1 mA h g^-1 even at a large current density of 3000 mA g^-1.

关键词： si MoS2 Medium capacity Long-term lifespan Lithium ion batteries

Effect of Ce addition on microstructures and mechanical properties of A380 aluminum alloy prepared by squeeze-casting

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International Journal of Minerals,Metallurgy and Materials 2018年第5期25卷 554-563页

作者： Xiao-hui Ao Shu-ming Xing Bai-shui Yu Qing-you Han School of Mechanical Electronic and Control Engineering Beijing Jiaotong University Department of Mechanical Engineering Technology Purdue University

The effect of cerium(Ce)addition on the eutectic si,β-Al_5Fe si phase,and the tensile properties of A380 alloy specimens prepared by squeeze-casting were studied by optical microscopy(OM),scanning electron microscopy(SEM),and X-ray diffraction(XRD).The experimental results showed that Ce more effectively modified the eutectic si and refined theβ-Al_5Fe si.The refinement effect significantly increased under a specific pressure of 100 MPa with the addition of Ce from 0.1wt%to 0.9wt%.In contrast,the average length and the aspect ratio of the eutectic si andβ-Al_5Fe si exhibited their optimal values when the content of the added Ce was greater than 0.5wt%.Needle-like Al_8Cu_4Ce was precipitated with the addition of excessive Ce;hence,the mechanical properties of A380 gradually decreased with increasing Ce content in the range from 0.3wt%to 0.9wt%.

关键词： cerium eutectic si Fe-rich phases squeeze-casting mechanical properties

Anti-Reflection Characteristics of si Nanowires for Enhanced Photoluminescence from CdTe/CdS Quantum Dots

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Chinese Physics Letters 2018年第5期35卷 91-94页

作者：王红玉单丹徐岭 Tongda College Nanjing University of Posts and Telecommunications National Laboratory of Solid State Microstructure and School of Electronic Science and Engineering Nanjing University School of Electronic and Information Engineering Yangzhou Polytechnic Institute

CdTe/CdS quantum dots（QDs） are fabricated on si nanowires（NWs） substrates with and without Au nanoparticles（NPs）. The formation of Au NPs on si NWs can be certified as shown in scanning electron microscopy images. The optical properties of samples are also investigated. It is interesting to find that the photoluminescence（PL） intensity of Cd Te/Cd S QD films on si nanowire substrates with Au NPs is significantly increased,which can reach 8-fold higher than that of samples on planar si without Au NPs. The results of finite-difference time-domain simulation indicate that Au NPs induce stronger localization of electric field and then boost the PL intensity of QDs nearby. Furthermore, the time-resolved luminescence decay curve shows the PL lifetime, which is about 5.5 ns at the emission peaks of QD films on planar, increasing from 1.8 ns of QD films on si NWs to4.7 ns after introducing Au NPs into si NWs.

关键词： si QDs Anti-Reflection Characteristics of si Nanowires for Enhanced Photoluminescence from CdTe/CdS Quantum Dots CdS

Nanoscale spatial phase modulation of GaAs growth in V-grooved trenches on si(001) substrate

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Chinese Physics B 2016年第12期25卷 451-454页

作者：李士颜周旭亮孔祥挺李梦珂米俊萍王梦琦潘教青 Key Laboratory of Semiconductor Materials Science Institute of SemiconductorsChinese Academy of Sciences

This letter reports the nanoscale spatial phase modulation of GaAs growth in V-grooved trenches fabricated on a si （001） substrate by metal-organic vapor-phase epitaxy, Two hexagonal GaAs regions with high density of stacking faults parallel to si {111 } surfaces are observed. A strain-relieved and defect-free cubic phase GaAs was achieved above these highly defective regions. High-resolution transmission electron microscopy and fast Fourier transforms analysis were performed to characterize these regions of GaAs/si interface. We also discussed the strain relaxation mechanism and phase structure modulation of GaAs selectively grown on this artificially manipulated surface.

关键词： phase modulation GaAs grooves si

A Partial 1100℃ Isotherm of Ti-Ni-si Ternary System

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Journal of Materials Science & Technology 1998年第2期14卷 121-124页

作者： Xiaohua HU Yimin LIU Guoliang CHEN and Kequan NI (State Key Lab. for Adv. Met. Mater., University of Science & Technology Beijing, Beijing 100083, China) State Key Lab. for Adv. Met. Mater. University of Science and Technology Beijing Beijing 100083 China

A partial section of Ti-Ni-si ternary system at 1100℃was constituted with Ni less than 50 at.pct. Twelve single phase areas were determined. The binary Ti3si phase proposed to occur at 1100℃ was not found in our investigations. A phase with the composition of Ni2Ti9si9 detected is possibly a new phase. No linear ternary compound was found. Some of these compounds show noticeable composition range

关键词： si Ti A Partial 1100 Isotherm of Ti-Ni-si Ternary System Ni

Electroluminescence Afterglow from Indium Tin Oxide/si-Rich siO2/p-si Structure

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Chinese Physics Letters 2006年第5期23卷 1306-1309页

作者：王晓欣张建国成步文余金中王启明 State Key Laboratory of Integrated Optoelectronics Institute of Semiconductors Chinese Academy of Sciences Beijing 100083

Indium tin oxide/si-rich siO2/p-si structured devices are fabricated to study the electroluminescence （EL） of the si-rich siO2 （SRO） material. The obvious peaks at～1050nm and ～1260nm in the EL are ascribed to localized state transitions of amorphous si （a-si） clusters. The EL afterglow associated with a-si clusters is observed from this structure at room temperature, while the afterglow is absent in the case of optical pumping. It is believed that carrier-induced defects act as trap centres in the a-si clusters, resulting in the EL afterglow. The phenomenon of the EL afterglow indicates the limits of EL performance and electrical modulation of the SRO material with a larger fraction of a-si clusters.

关键词： siLICON NANOCRYSTALS si PHOTOLUMINESCENCE EVOLUTION

Spherical silicon solar cell with reflector cup fabricated by decompression dropping method

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Rare Metals 2006年第Z1期25卷 121-126页

作者： MINEMOTO Takashi OKAMOTO Chikao MUROZONO Mikio TAKAKURA Hideyuki HAMAKAWA Yoshihiro College of Science and Engineering Ritsumeikan University 1-1-1 Nojihigashi Kusatsu Shiga 525-8577 Japan Clean Venture 21 Co. Ltd. 35 Kamitoba Daimotsu-chou Minami-ku Kyoto 601-8121 Japan

A spherical si solar cell with a reflector cup was successfully fabricated by a dropping method at decompression state. In the dropping method, melted si droplets were instilled at decompression state (0.5×105 Pa) to reduce crystal growth rate, dominating crystal quality such as dislocation density in crystal grains. Spherical si solar cells were fabricated using the spherical si crystals with a diameter of 1 mm and then mounted on a reflector cup. The current-voltage measurement of the solar cell shows an energy conversion efficiency of 11.1% (short-circuit current density (Jsc): 24.7 mA·cm-2, open-circuit voltage: 601 mV, fill factor: 74.6%). Minority carrier diffusion length determined by surface photovoltage method was 98 μm. This value can be enhanced by the improvement of crystal quality of spherical si crystals. These results demonstrate that spherical si crystals fabricated by the dropping method has a great potential for substrate material of high-efficiency and low-cost solar cells.

关键词： spherical si solar cell dropping method decompression state