The Experts below are selected from a list of 5166 Experts worldwide ranked by ideXlab platform
Zhiyong Fan - One of the best experts on this subject based on the ideXlab platform.
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rational geometrical design of multi diameter Nanopillars for efficient light harvesting
Nano Energy, 2013Co-Authors: Bo Hua, Paul W. Leu, Baomin Wang, Zhiyong FanAbstract:Abstract Three-dimensional arrays of nanostructures have drawn increasing attention for solar energy harvesting in recent years. In this work, with Ge as the model material, the broadband solar spectrum absorption of arrays of multi-diameter Nanopillars is explored with finite difference time domain simulations. It is found that light absorption of a nanopillar array is either determined by the material filling ratio or by transverse resonance leaky modes depending on input wavelength. A properly designed multi-diameter nanopillar array can compete with a nanocone array on broadband light absorption capability. As single crystalline multi-diameter Nanopillars can be grown with a bottom-up approach, the investigation here provides important design guidelines for the fabrication of efficient nanostructured photovoltaic and other optoelectronic devices.
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shape controlled synthesis of single crystalline nanopillar arrays by template assisted vapor liquid solid process
Journal of the American Chemical Society, 2010Co-Authors: Onur Ergen, Daniel J. Ruebusch, Asghar A. Rathore, Zhiyong Fan, Rehan Kapadia, Hui Fang, Kuniharu Takei, Arash Jamshidi, Ali JaveyAbstract:Highly regular, single-crystalline nanopillar arrays with tunable shapes and geometry are synthesized by the template-assisted vapor−liquid−solid growth mechanism. In this approach, the grown Nanopillars faithfully reproduce the shape of the pores because during the growth the liquid catalyst seeds fill the space available, thereby conforming to the pore geometry. The process is highly generic for various material systems, and as an example, CdS and Ge nanopillar arrays with square, rectangular, and circular cross sections are demonstrated. In the future, this technique can be used to engineer the intrinsic properties of NPLs as a function of three independently controlled dimensional parameters - length, width and height.
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Challenges and prospects of nanopillar-based solar cells
Nano Research, 2009Co-Authors: Zhiyong Fan, Onur Ergen, Daniel J. Ruebusch, Asghar A. Rathore, Paul W. Leu, Rehan Kapadia, Ali JaveyAbstract:Materials and device architecture innovations are essential for further enhancing the performance of solar cells while potentially enabling their large-scale integration as a viable source of alternative energy. In this regard, tremendous research has been devoted in recent years with continuous progress in the field. In this article, we review the recent advancements in nanopillar-based photovoltaics while discussing the future challenges and prospects. Nanopillar arrays provide unique advantages over thin films in the areas of optical properties and carrier collection, arising from their three-dimensional geometry. The choice of the material system, however, is essential in order to gain the advantage of the large surface/interface area associated with Nanopillars with the constraints different from those of the thin film devices.
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three dimensional nanopillar array photovoltaics on low cost and flexible substrates
Nature Materials, 2009Co-Authors: Aimee Moriwaki, Onur Ergen, Haleh Razavi, Zhiyong Fan, Yu-lun ChuehAbstract:Solar power is an important part of the strategy towards using more renewable energy. The development of low-cost photovoltaic nanopillar structures fabricated on thin aluminium substrates will contribute to this effort, as it promises new applications for flexible, mass-produced solar cells. Solar energy represents one of the most abundant and yet least harvested sources of renewable energy. In recent years, tremendous progress has been made in developing photovoltaics that can be potentially mass deployed1,2,3. Of particular interest to cost-effective solar cells is to use novel device structures and materials processing for enabling acceptable efficiencies4,5,6. In this regard, here, we report the direct growth of highly regular, single-crystalline nanopillar arrays of optically active semiconductors on aluminium substrates that are then configured as solar-cell modules. As an example, we demonstrate a photovoltaic structure that incorporates three-dimensional, single-crystalline n-CdS Nanopillars, embedded in polycrystalline thin films of p-CdTe, to enable high absorption of light and efficient collection of the carriers. Through experiments and modelling, we demonstrate the potency of this approach for enabling highly versatile solar modules on both rigid and flexible substrates with enhanced carrier collection efficiency arising from the geometric configuration of the Nanopillars.
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Three-dimensional nanopillar-array photovoltaics on low-cost and flexible substrates
Nature Materials, 2009Co-Authors: Zhiyong Fan, Aimee Moriwaki, Onur Ergen, Jae Won Do, Haleh Razavi, Toshitake Takahashi, Paul W. Leu, Johnny C. Ho, Yu-lun Chueh, Lothar A. ReichertzAbstract:Solar energy represents one of the most abundant and yet\nleast harvested sources of renewable energy. In recent years,\ntremendous progress has been made in developing photovoltaics\nthat can be potentially mass deployed1–3. Of particular\ninterest to cost-effective solar cells is to use novel\ndevice structures and materials processing for enabling acceptable\nefficiencies4–6. In this regard, here, we report the direct\ngrowth of highly regular, single-crystalline nanopillar arrays\nof optically active semiconductors on aluminium substrates\nthat are then configured as solar-cell modules. As an example,\nwe demonstrate a photovoltaic structure that incorporates\nthree-dimensional, single-crystalline n-CdS Nanopillars,\nembedded in polycrystalline thin films of p-CdTe, to enable\nhigh absorption of light and efficient collection of the carriers.\nThrough experiments and modelling, we demonstrate the\npotency of this approach for enabling highly versatile solar\nmodules on both rigid and flexible substrates with enhanced\ncarrier collection efficiency arising from the geometric configuration\nof the Nanopillars.
Onur Ergen - One of the best experts on this subject based on the ideXlab platform.
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molecular monolayers for conformal nanoscale doping of inp nanopillar photovoltaics
Applied Physics Letters, 2011Co-Authors: Kee Young Cho, Onur Ergen, Daniel J. Ruebusch, Rehan Kapadia, Min Hyung Lee, Kuniharu Takei, Jaehyun Moon, Alexandra C Ford, Ali JaveyAbstract:Semiconductor nanopillar arrays with radially doped junctions have been widely proposed as an attractive device architecture for cost effective and high efficiency solar cells. A challenge in the fabrication of three-dimensional nanopillar devices is the need for highly abrupt and conformal junctions along the radial axes. Here, a sulfur monolayer doping scheme is implemented to achieve conformal ultrashallow junctions with sub-10 nm depths and a high electrically active dopant concentration of 1019–1020 cm−3 in arrays of InP Nanopillars. The enabled solar cells exhibit a respectable conversion efficiency of 8.1% and a short circuit current density of 25 mA/cm3. The work demonstrates the utility of well-established surface chemistry for fabrication of nonplanar junctions for complex devices.
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shape controlled synthesis of single crystalline nanopillar arrays by template assisted vapor liquid solid process
Journal of the American Chemical Society, 2010Co-Authors: Onur Ergen, Daniel J. Ruebusch, Asghar A. Rathore, Zhiyong Fan, Rehan Kapadia, Hui Fang, Kuniharu Takei, Arash Jamshidi, Ali JaveyAbstract:Highly regular, single-crystalline nanopillar arrays with tunable shapes and geometry are synthesized by the template-assisted vapor−liquid−solid growth mechanism. In this approach, the grown Nanopillars faithfully reproduce the shape of the pores because during the growth the liquid catalyst seeds fill the space available, thereby conforming to the pore geometry. The process is highly generic for various material systems, and as an example, CdS and Ge nanopillar arrays with square, rectangular, and circular cross sections are demonstrated. In the future, this technique can be used to engineer the intrinsic properties of NPLs as a function of three independently controlled dimensional parameters - length, width and height.
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Challenges and prospects of nanopillar-based solar cells
Nano Research, 2009Co-Authors: Zhiyong Fan, Onur Ergen, Daniel J. Ruebusch, Asghar A. Rathore, Paul W. Leu, Rehan Kapadia, Ali JaveyAbstract:Materials and device architecture innovations are essential for further enhancing the performance of solar cells while potentially enabling their large-scale integration as a viable source of alternative energy. In this regard, tremendous research has been devoted in recent years with continuous progress in the field. In this article, we review the recent advancements in nanopillar-based photovoltaics while discussing the future challenges and prospects. Nanopillar arrays provide unique advantages over thin films in the areas of optical properties and carrier collection, arising from their three-dimensional geometry. The choice of the material system, however, is essential in order to gain the advantage of the large surface/interface area associated with Nanopillars with the constraints different from those of the thin film devices.
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three dimensional nanopillar array photovoltaics on low cost and flexible substrates
Nature Materials, 2009Co-Authors: Aimee Moriwaki, Onur Ergen, Haleh Razavi, Zhiyong Fan, Yu-lun ChuehAbstract:Solar power is an important part of the strategy towards using more renewable energy. The development of low-cost photovoltaic nanopillar structures fabricated on thin aluminium substrates will contribute to this effort, as it promises new applications for flexible, mass-produced solar cells. Solar energy represents one of the most abundant and yet least harvested sources of renewable energy. In recent years, tremendous progress has been made in developing photovoltaics that can be potentially mass deployed1,2,3. Of particular interest to cost-effective solar cells is to use novel device structures and materials processing for enabling acceptable efficiencies4,5,6. In this regard, here, we report the direct growth of highly regular, single-crystalline nanopillar arrays of optically active semiconductors on aluminium substrates that are then configured as solar-cell modules. As an example, we demonstrate a photovoltaic structure that incorporates three-dimensional, single-crystalline n-CdS Nanopillars, embedded in polycrystalline thin films of p-CdTe, to enable high absorption of light and efficient collection of the carriers. Through experiments and modelling, we demonstrate the potency of this approach for enabling highly versatile solar modules on both rigid and flexible substrates with enhanced carrier collection efficiency arising from the geometric configuration of the Nanopillars.
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Three-dimensional nanopillar-array photovoltaics on low-cost and flexible substrates
Nature Materials, 2009Co-Authors: Zhiyong Fan, Aimee Moriwaki, Onur Ergen, Jae Won Do, Haleh Razavi, Toshitake Takahashi, Paul W. Leu, Johnny C. Ho, Yu-lun Chueh, Lothar A. ReichertzAbstract:Solar energy represents one of the most abundant and yet\nleast harvested sources of renewable energy. In recent years,\ntremendous progress has been made in developing photovoltaics\nthat can be potentially mass deployed1–3. Of particular\ninterest to cost-effective solar cells is to use novel\ndevice structures and materials processing for enabling acceptable\nefficiencies4–6. In this regard, here, we report the direct\ngrowth of highly regular, single-crystalline nanopillar arrays\nof optically active semiconductors on aluminium substrates\nthat are then configured as solar-cell modules. As an example,\nwe demonstrate a photovoltaic structure that incorporates\nthree-dimensional, single-crystalline n-CdS Nanopillars,\nembedded in polycrystalline thin films of p-CdTe, to enable\nhigh absorption of light and efficient collection of the carriers.\nThrough experiments and modelling, we demonstrate the\npotency of this approach for enabling highly versatile solar\nmodules on both rigid and flexible substrates with enhanced\ncarrier collection efficiency arising from the geometric configuration\nof the Nanopillars.
Tony Jun Huang - One of the best experts on this subject based on the ideXlab platform.
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Multifunctional porous silicon nanopillar arrays: antireflection, superhydrophobicity, photoluminescence, and surface-enhanced Raman scattering Multifunctional porous silicon nanopillar arrays: antireflection, superhydrophobicity, photoluminescence, and s
2020Co-Authors: Brian Kiraly, Shikuan Yang, Tony Jun HuangAbstract:Abstract We have fabricated porous silicon nanopillar arrays over large areas with a rapid, simple, and low-cost technique. The porous silicon Nanopillars show unique longitudinal features along their entire length and have porosity with dimensions on the single-nanometer scale. Both Raman spectroscopy and photoluminescence data were used to determine the nanocrystallite size to be <3 nm. The porous silicon nanopillar arrays also maintained excellent ensemble properties, reducing reflection nearly fivefold from planar silicon in the visible range without any optimization, and approaching superhydrophobic behavior with increasing aspect ratio, demonstrating contact angles up to 138 • . Finally, the porous silicon nanopillar arrays were made into sensitive surface-enhanced Raman scattering (SERS) substrates by depositing metal onto the pillars. The SERS performance of the substrates was demonstrated using a chemical dye Rhodamine 6G. With their multitude of properties (i.e., antireflection, superhydrophobicity, photoluminescence, and sensitive SERS), the porous silicon nanopillar arrays described here can be valuable in applications such as solar harvesting, electrochemical cells, self-cleaning devices, and dynamic biological monitoring
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multifunctional porous silicon nanopillar arrays antireflection superhydrophobicity photoluminescence and surface enhanced raman scattering
Nanotechnology, 2013Co-Authors: Brian Kiraly, Shikuan Yang, Tony Jun HuangAbstract:We have fabricated porous silicon nanopillar arrays over large areas with a rapid, simple, and low-cost technique. The porous silicon Nanopillars show unique longitudinal features along their entire length and have porosity with dimensions on the single-nanometer scale. Both Raman spectroscopy and photoluminescence data were used to determine the nanocrystallite size to be <3 nm. The porous silicon nanopillar arrays also maintained excellent ensemble properties, reducing reflection nearly fivefold from planar silicon in the visible range without any optimization, and approaching superhydrophobic behavior with increasing aspect ratio, demonstrating contact angles up to 138°. Finally, the porous silicon nanopillar arrays were made into sensitive surface-enhanced Raman scattering (SERS) substrates by depositing metal onto the pillars. The SERS performance of the substrates was demonstrated using a chemical dye Rhodamine 6G. With their multitude of properties (i.e., antireflection, superhydrophobicity, photoluminescence, and sensitive SERS), the porous silicon nanopillar arrays described here can be valuable in applications such as solar harvesting, electrochemical cells, self-cleaning devices, and dynamic biological monitoring.
Ali Javey - One of the best experts on this subject based on the ideXlab platform.
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molecular monolayers for conformal nanoscale doping of inp nanopillar photovoltaics
Applied Physics Letters, 2011Co-Authors: Kee Young Cho, Onur Ergen, Daniel J. Ruebusch, Rehan Kapadia, Min Hyung Lee, Kuniharu Takei, Jaehyun Moon, Alexandra C Ford, Ali JaveyAbstract:Semiconductor nanopillar arrays with radially doped junctions have been widely proposed as an attractive device architecture for cost effective and high efficiency solar cells. A challenge in the fabrication of three-dimensional nanopillar devices is the need for highly abrupt and conformal junctions along the radial axes. Here, a sulfur monolayer doping scheme is implemented to achieve conformal ultrashallow junctions with sub-10 nm depths and a high electrically active dopant concentration of 1019–1020 cm−3 in arrays of InP Nanopillars. The enabled solar cells exhibit a respectable conversion efficiency of 8.1% and a short circuit current density of 25 mA/cm3. The work demonstrates the utility of well-established surface chemistry for fabrication of nonplanar junctions for complex devices.
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shape controlled synthesis of single crystalline nanopillar arrays by template assisted vapor liquid solid process
Journal of the American Chemical Society, 2010Co-Authors: Onur Ergen, Daniel J. Ruebusch, Asghar A. Rathore, Zhiyong Fan, Rehan Kapadia, Hui Fang, Kuniharu Takei, Arash Jamshidi, Ali JaveyAbstract:Highly regular, single-crystalline nanopillar arrays with tunable shapes and geometry are synthesized by the template-assisted vapor−liquid−solid growth mechanism. In this approach, the grown Nanopillars faithfully reproduce the shape of the pores because during the growth the liquid catalyst seeds fill the space available, thereby conforming to the pore geometry. The process is highly generic for various material systems, and as an example, CdS and Ge nanopillar arrays with square, rectangular, and circular cross sections are demonstrated. In the future, this technique can be used to engineer the intrinsic properties of NPLs as a function of three independently controlled dimensional parameters - length, width and height.
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Challenges and prospects of nanopillar-based solar cells
Nano Research, 2009Co-Authors: Zhiyong Fan, Onur Ergen, Daniel J. Ruebusch, Asghar A. Rathore, Paul W. Leu, Rehan Kapadia, Ali JaveyAbstract:Materials and device architecture innovations are essential for further enhancing the performance of solar cells while potentially enabling their large-scale integration as a viable source of alternative energy. In this regard, tremendous research has been devoted in recent years with continuous progress in the field. In this article, we review the recent advancements in nanopillar-based photovoltaics while discussing the future challenges and prospects. Nanopillar arrays provide unique advantages over thin films in the areas of optical properties and carrier collection, arising from their three-dimensional geometry. The choice of the material system, however, is essential in order to gain the advantage of the large surface/interface area associated with Nanopillars with the constraints different from those of the thin film devices.
Yu-lun Chueh - One of the best experts on this subject based on the ideXlab platform.
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three dimensional nanopillar array photovoltaics on low cost and flexible substrates
Nature Materials, 2009Co-Authors: Aimee Moriwaki, Onur Ergen, Haleh Razavi, Zhiyong Fan, Yu-lun ChuehAbstract:Solar power is an important part of the strategy towards using more renewable energy. The development of low-cost photovoltaic nanopillar structures fabricated on thin aluminium substrates will contribute to this effort, as it promises new applications for flexible, mass-produced solar cells. Solar energy represents one of the most abundant and yet least harvested sources of renewable energy. In recent years, tremendous progress has been made in developing photovoltaics that can be potentially mass deployed1,2,3. Of particular interest to cost-effective solar cells is to use novel device structures and materials processing for enabling acceptable efficiencies4,5,6. In this regard, here, we report the direct growth of highly regular, single-crystalline nanopillar arrays of optically active semiconductors on aluminium substrates that are then configured as solar-cell modules. As an example, we demonstrate a photovoltaic structure that incorporates three-dimensional, single-crystalline n-CdS Nanopillars, embedded in polycrystalline thin films of p-CdTe, to enable high absorption of light and efficient collection of the carriers. Through experiments and modelling, we demonstrate the potency of this approach for enabling highly versatile solar modules on both rigid and flexible substrates with enhanced carrier collection efficiency arising from the geometric configuration of the Nanopillars.
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Three-dimensional nanopillar-array photovoltaics on low-cost and flexible substrates
Nature Materials, 2009Co-Authors: Zhiyong Fan, Aimee Moriwaki, Onur Ergen, Jae Won Do, Haleh Razavi, Toshitake Takahashi, Paul W. Leu, Johnny C. Ho, Yu-lun Chueh, Lothar A. ReichertzAbstract:Solar energy represents one of the most abundant and yet\nleast harvested sources of renewable energy. In recent years,\ntremendous progress has been made in developing photovoltaics\nthat can be potentially mass deployed1–3. Of particular\ninterest to cost-effective solar cells is to use novel\ndevice structures and materials processing for enabling acceptable\nefficiencies4–6. In this regard, here, we report the direct\ngrowth of highly regular, single-crystalline nanopillar arrays\nof optically active semiconductors on aluminium substrates\nthat are then configured as solar-cell modules. As an example,\nwe demonstrate a photovoltaic structure that incorporates\nthree-dimensional, single-crystalline n-CdS Nanopillars,\nembedded in polycrystalline thin films of p-CdTe, to enable\nhigh absorption of light and efficient collection of the carriers.\nThrough experiments and modelling, we demonstrate the\npotency of this approach for enabling highly versatile solar\nmodules on both rigid and flexible substrates with enhanced\ncarrier collection efficiency arising from the geometric configuration\nof the Nanopillars.
