Silicon-based nanomaterials have been of scientific and commercial interest in lithium-ion batteries due to the low cost,low toxicity,and high specific capacity with an order of magnitude beyond that of conventional g...Silicon-based nanomaterials have been of scientific and commercial interest in lithium-ion batteries due to the low cost,low toxicity,and high specific capacity with an order of magnitude beyond that of conventional graphite.The poor capacity retention,caused by pulverization of Si during cycling,triggers researchers and engineers to explore better battery materials.This review summarizes recent work in improving Si-based anode materials via different approaches from diverse Si nanostructures,Si/metal nanocomposites,to Si/C nanocomposites,and also offers perspectives of the Si-based anode materials.展开更多
This review outlines the developments and recent progress in metal-assisted chemical etching of silicon, summarizing a variety of fundamental and innovative processes and etching methods that form a wide range of nano...This review outlines the developments and recent progress in metal-assisted chemical etching of silicon, summarizing a variety of fundamental and innovative processes and etching methods that form a wide range of nanoscale silicon structures. The use of silicon as an anode for Li-ion batteries is also reviewed, where factors such as film thickness, doping, alloying, and their response to reversible lithiation processes are summarized and discussed with respect to battery cell performance. Recent advances in improving the performance of silicon-based anodes in Li-ion batteries are also discussed. The use of a variety of nanostructured silicon structures formed by many different methods as Li-ion battery anodes is outlined, focusing in particular on the influence of mass loading, core-shell structure, conductive additives, and other parameters. The influence of porosity, dopant type, and doping level on the electrochemical response and cell performance of the silicon anodes are detailed based on recent findings. Perspectives on the future of silicon and related materials, and their compositional and structural modifications for energy storage via several electrochemical mechanisms, are also provided.展开更多
It is found that 5,10,15,20-tetrakis(4-sulfonatophenyl) porphyrin(TPPS),which is known to form J aggregates in water under low pH value,acts as a template for the hydrolyzing of organosilane.The nanotube structures of...It is found that 5,10,15,20-tetrakis(4-sulfonatophenyl) porphyrin(TPPS),which is known to form J aggregates in water under low pH value,acts as a template for the hydrolyzing of organosilane.The nanotube structures of silica with 4 8 nm inner diameters are obtained,which is consistent with the height of TPPS J aggregates,indicating that TPPS J aggregates are indeed acting as the template for the sol-gel transcription.The TPPS J aggregation disappear when the medium pH value is shifted from acidic to basic,consequently formed silica nanostructures are amorphous nanosphere rather than nanofiber structures.In contrast,the copper phthalocyanine(TSCuPc),which does not exist as linear J aggregates,cannot induce the silica to form one dimensional nanofiber structures,implying that the templating effect of TPPS J aggregates for inorganic nanostructures.展开更多
通过制备面向MEMS红外光源的高辐射率多晶硅纳米柱状结构和单晶硅纳米孔结构,以提升红外源表面辐射率,降低器件功耗。制备方法分别为反应离子刻蚀(reactive-ion-etching,RIE)及等离子浸没离子注入(plasma immerse ion implantation,PIII...通过制备面向MEMS红外光源的高辐射率多晶硅纳米柱状结构和单晶硅纳米孔结构,以提升红外源表面辐射率,降低器件功耗。制备方法分别为反应离子刻蚀(reactive-ion-etching,RIE)及等离子浸没离子注入(plasma immerse ion implantation,PIII)工艺对单晶硅以及铝电极掩膜的多晶硅表面调控修饰制备。并对2种纳米硅结构进行了吸收率测试,对铝电极掩膜进行了引线键合破坏拉力测试。测试表明,纳米硅结构在3~5μm波段的辐射率可以达到85%以上,暴露在刻蚀气氛后的铝电极掩膜引线键合强度可以达到器件工艺要求。展开更多
The amorphous silicon nanoparticles (Si NPs) embedded in silicon nitride (SiNx) films prepared by helicon wave plasma-enhanced chemical vapor deposition (HWP-CVD) technique are studied. From Raman scattering inv...The amorphous silicon nanoparticles (Si NPs) embedded in silicon nitride (SiNx) films prepared by helicon wave plasma-enhanced chemical vapor deposition (HWP-CVD) technique are studied. From Raman scattering investigation, we determine that the deposited film has the structure of silicon nanocrystals embedded in silicon nitride (nc-Si/SiNx) thin film at a certain hydrogen dilution amount. The analysis of optical absorption spectra implies that the Si NPs is affected by quantum size effects and has the nature of an indirect-band-gap semiconductor. Further, considering the effects of the mean Si NP size and their dispersion on oscillator strength, and quantum-confinement, we obtain an analytical expression for the spectral absorbance of ensemble samples. Gaussian as well as lognormal size-distributions of the Si NPs are considered for optical absorption coefficient calculations. The influence of the particle size-distribution on the optical absorption spectra was systematically studied. We present the fitting of the optical absorption experimental data with our model and discuss the results.展开更多
MnSi in the B20 structure is a prototypical helimagnet that forms a skyrmion lattice, a vortex-like spin texture under applied magnetic field. We have systematically explored the synthesis of single crystal MnSi nanow...MnSi in the B20 structure is a prototypical helimagnet that forms a skyrmion lattice, a vortex-like spin texture under applied magnetic field. We have systematically explored the synthesis of single crystal MnSi nanowires via controlled oxide-assisted chemical vapor deposition and observed a characteristic signature of skyrmion magnetic ordering in the MnSi nanowires. The thickness of the SiO2 layer on the Si substrate plays the key role in obtaining a high yield of B20 MnSi skyrmion nanowires. A growth mechanism was proposed that is consistent with the existence of an optimum SiO2 thickness. A growth phase diagram was constructed based on the extensive studies of various growth conditions for various MnSi nanostructures. The persistence of both the helicoidal and skyrmion magnetic ordering in the one-dimensional wires was directly revealed by ac and dc magnetic measurements.展开更多
Porous silicon (PS) was fabricated by laser-induced etching (LIE) process. The objective of this study is to investigate the selected LIE parameters to control size and shape of nanostructures,which are considered imp...Porous silicon (PS) was fabricated by laser-induced etching (LIE) process. The objective of this study is to investigate the selected LIE parameters to control size and shape of nanostructures,which are considered important factors in semiconductor device applications. Photoluminescence output intensity becomes stronger due to the increase in the number of emitted photons on the porous surface. There is a dramatic increase in photoluminescence intensity due to the increase of porosity as a function of laser power density. The increase in electrolyte concentration is an important parameter to accelerate the dissolution reaction on the interface layer between the electrolyte solution and wafer surface. PS spectra displayed a stronger Raman intensity than crystalline bulk Si;also the PS spectrum was shifted and broadened as a function of LIE parameters.展开更多
Silicon crystal-facet-dependent nanostructures have been successfully fabricated on a (100)-oriented silicon-oninsulator wafer using electron-beam lithography and the silicon anisotropic wet etching technique. This ...Silicon crystal-facet-dependent nanostructures have been successfully fabricated on a (100)-oriented silicon-oninsulator wafer using electron-beam lithography and the silicon anisotropic wet etching technique. This technique takes advantage of the large difference in etching properties for different crystallographic planes in alkaline solution. The minimum size of the trapezoidal top for those Si nanostructures can be reduced to less than 10nm. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) observations indicate that the etched nanostructures have controllable shapes and smooth surfaces.展开更多
The broad availability of high throughput nanostructure fabrication is essential for advancement in nanoscale science. Large-scale manufacturing developed by the semiconductor industry is often too resource-intensive ...The broad availability of high throughput nanostructure fabrication is essential for advancement in nanoscale science. Large-scale manufacturing developed by the semiconductor industry is often too resource-intensive for medium scale laboratory prototyping. We demonstrate the inexpensive wafer scale direct- write of Ge and Si nanostructures with a 4-inch mask aligner retrofitted with a conducting microstructured stamp. A bias applied between the stamp and an underlying silicon substrate results in the reaction of diphenylgermane and diphenylsilane precursors at the stamp--substrate interface to yield the direct- write of Ge and Si nanostructures in determined locations. With the increasing number of outdated mask aligners available from the semiconductor industry and an extensive library of liquid precursors, this strategy provides facile, inexpensive, wafer scale semiconductor direct-write for applications such as electronics, photonics, and photovoltaics.展开更多
基金supported by the National Basic Research Program of China (2011CB935700 and 2012CB932900)the National Natural Science Foundation of China (91127044 and 21073205)the Chinese Academy of Sciences
文摘Silicon-based nanomaterials have been of scientific and commercial interest in lithium-ion batteries due to the low cost,low toxicity,and high specific capacity with an order of magnitude beyond that of conventional graphite.The poor capacity retention,caused by pulverization of Si during cycling,triggers researchers and engineers to explore better battery materials.This review summarizes recent work in improving Si-based anode materials via different approaches from diverse Si nanostructures,Si/metal nanocomposites,to Si/C nanocomposites,and also offers perspectives of the Si-based anode materials.
基金WMS acknowledges support under the framework of the INSPIRE programme, funded by the Irish Government's Programme for Research in Third Level Institutions, Cycle 4, National Development Plan 2007-2013. COD acknowledges support from Science Foundation Ireland under Award No. 07/SK/ B1232a-STTF11 from the UCC Strategic Research Fund.
文摘This review outlines the developments and recent progress in metal-assisted chemical etching of silicon, summarizing a variety of fundamental and innovative processes and etching methods that form a wide range of nanoscale silicon structures. The use of silicon as an anode for Li-ion batteries is also reviewed, where factors such as film thickness, doping, alloying, and their response to reversible lithiation processes are summarized and discussed with respect to battery cell performance. Recent advances in improving the performance of silicon-based anodes in Li-ion batteries are also discussed. The use of a variety of nanostructured silicon structures formed by many different methods as Li-ion battery anodes is outlined, focusing in particular on the influence of mass loading, core-shell structure, conductive additives, and other parameters. The influence of porosity, dopant type, and doping level on the electrochemical response and cell performance of the silicon anodes are detailed based on recent findings. Perspectives on the future of silicon and related materials, and their compositional and structural modifications for energy storage via several electrochemical mechanisms, are also provided.
基金supported by the National Basic Research Program of China (2009CB930802)the National Natural Science Foundation of China(91027042,21021003)the Fund of the Chinese Academy of Sciences
文摘It is found that 5,10,15,20-tetrakis(4-sulfonatophenyl) porphyrin(TPPS),which is known to form J aggregates in water under low pH value,acts as a template for the hydrolyzing of organosilane.The nanotube structures of silica with 4 8 nm inner diameters are obtained,which is consistent with the height of TPPS J aggregates,indicating that TPPS J aggregates are indeed acting as the template for the sol-gel transcription.The TPPS J aggregation disappear when the medium pH value is shifted from acidic to basic,consequently formed silica nanostructures are amorphous nanosphere rather than nanofiber structures.In contrast,the copper phthalocyanine(TSCuPc),which does not exist as linear J aggregates,cannot induce the silica to form one dimensional nanofiber structures,implying that the templating effect of TPPS J aggregates for inorganic nanostructures.
文摘通过制备面向MEMS红外光源的高辐射率多晶硅纳米柱状结构和单晶硅纳米孔结构,以提升红外源表面辐射率,降低器件功耗。制备方法分别为反应离子刻蚀(reactive-ion-etching,RIE)及等离子浸没离子注入(plasma immerse ion implantation,PIII)工艺对单晶硅以及铝电极掩膜的多晶硅表面调控修饰制备。并对2种纳米硅结构进行了吸收率测试,对铝电极掩膜进行了引线键合破坏拉力测试。测试表明,纳米硅结构在3~5μm波段的辐射率可以达到85%以上,暴露在刻蚀气氛后的铝电极掩膜引线键合强度可以达到器件工艺要求。
基金Supported by the National Natural Science Foundation of China under Grant No.60940020the Natural Foundation of Hebei Province under Grant No.E2008000619
文摘The amorphous silicon nanoparticles (Si NPs) embedded in silicon nitride (SiNx) films prepared by helicon wave plasma-enhanced chemical vapor deposition (HWP-CVD) technique are studied. From Raman scattering investigation, we determine that the deposited film has the structure of silicon nanocrystals embedded in silicon nitride (nc-Si/SiNx) thin film at a certain hydrogen dilution amount. The analysis of optical absorption spectra implies that the Si NPs is affected by quantum size effects and has the nature of an indirect-band-gap semiconductor. Further, considering the effects of the mean Si NP size and their dispersion on oscillator strength, and quantum-confinement, we obtain an analytical expression for the spectral absorbance of ensemble samples. Gaussian as well as lognormal size-distributions of the Si NPs are considered for optical absorption coefficient calculations. The influence of the particle size-distribution on the optical absorption spectra was systematically studied. We present the fitting of the optical absorption experimental data with our model and discuss the results.
文摘MnSi in the B20 structure is a prototypical helimagnet that forms a skyrmion lattice, a vortex-like spin texture under applied magnetic field. We have systematically explored the synthesis of single crystal MnSi nanowires via controlled oxide-assisted chemical vapor deposition and observed a characteristic signature of skyrmion magnetic ordering in the MnSi nanowires. The thickness of the SiO2 layer on the Si substrate plays the key role in obtaining a high yield of B20 MnSi skyrmion nanowires. A growth mechanism was proposed that is consistent with the existence of an optimum SiO2 thickness. A growth phase diagram was constructed based on the extensive studies of various growth conditions for various MnSi nanostructures. The persistence of both the helicoidal and skyrmion magnetic ordering in the one-dimensional wires was directly revealed by ac and dc magnetic measurements.
文摘Porous silicon (PS) was fabricated by laser-induced etching (LIE) process. The objective of this study is to investigate the selected LIE parameters to control size and shape of nanostructures,which are considered important factors in semiconductor device applications. Photoluminescence output intensity becomes stronger due to the increase in the number of emitted photons on the porous surface. There is a dramatic increase in photoluminescence intensity due to the increase of porosity as a function of laser power density. The increase in electrolyte concentration is an important parameter to accelerate the dissolution reaction on the interface layer between the electrolyte solution and wafer surface. PS spectra displayed a stronger Raman intensity than crystalline bulk Si;also the PS spectrum was shifted and broadened as a function of LIE parameters.
文摘Silicon crystal-facet-dependent nanostructures have been successfully fabricated on a (100)-oriented silicon-oninsulator wafer using electron-beam lithography and the silicon anisotropic wet etching technique. This technique takes advantage of the large difference in etching properties for different crystallographic planes in alkaline solution. The minimum size of the trapezoidal top for those Si nanostructures can be reduced to less than 10nm. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) observations indicate that the etched nanostructures have controllable shapes and smooth surfaces.
文摘The broad availability of high throughput nanostructure fabrication is essential for advancement in nanoscale science. Large-scale manufacturing developed by the semiconductor industry is often too resource-intensive for medium scale laboratory prototyping. We demonstrate the inexpensive wafer scale direct- write of Ge and Si nanostructures with a 4-inch mask aligner retrofitted with a conducting microstructured stamp. A bias applied between the stamp and an underlying silicon substrate results in the reaction of diphenylgermane and diphenylsilane precursors at the stamp--substrate interface to yield the direct- write of Ge and Si nanostructures in determined locations. With the increasing number of outdated mask aligners available from the semiconductor industry and an extensive library of liquid precursors, this strategy provides facile, inexpensive, wafer scale semiconductor direct-write for applications such as electronics, photonics, and photovoltaics.