The Experts below are selected from a list of 21126 Experts worldwide ranked by ideXlab platform
Charles M. Lieber - One of the best experts on this subject based on the ideXlab platform.
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Coherent single charge transport in Molecular-Scale silicon nanowires.
Nano letters, 2005Co-Authors: Charles M. LieberAbstract:We report low-temperature electrical transport studies of chemically synthesized, Molecular-Scale silicon nanowires. Individual nanowires exhibit Coulomb blockade oscillations characteristic of charge addition to a single nanostructure on length Scales up to at least 400 nm. Studies also demonstrate coherent charge transport through discrete single particle quantum levels extending across whole devices, and show that the ground-state spin configuration is consistent with the constant interaction model. In addition, depletion of nanowires suggests that phase coherent single-dot characteristics are accessible in the few-charge regime. These results differ from those for nanofabricated planar silicon devices, which show localization on much shorter length Scales, and thus suggest potential for Molecular-Scale silicon nanowires as building blocks for quantum and conventional electronics.
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Controlled Growth and Structures of Molecular-Scale Silicon Nanowires
Nano Letters, 2004Co-Authors: Yue Wu, Carl J. Barrelet, Yi Cui, David C. Bell, Lynn Huynh, Charles M. LieberAbstract:Single-crystal silicon nanowires with diameters approaching Molecular dimensions were synthesized using gold nanocluster-catalyzed 1D growth. High-resolution transmission electron microscopy studies show that silicon nanowires grown with silane reactant in hydrogen are single crystal with little or no visible amorphous oxide down to diameters as small as 3 nm. Structural characterization of a large number of samples shows that the smallest-diameter nanowires grow primarily along the ?110? direction, whereas larger nanowires grow along the ?111? direction. In addition, cross-sectional transmission electron microscopy was used to address the importance of surface energetics in determining the growth direction of the smallest nanowires. The ability to prepare well-defined Molecular-Scale single-crystal silicon nanowires opens up new opportunities for both fundamental studies and nanodevice applications.
John A Rogers - One of the best experts on this subject based on the ideXlab platform.
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Molecular-Scale soft imprint lithography for alignment layers in liquid crystal devices
Nano Letters, 2007Co-Authors: John A RogersAbstract:We describe Molecular-Scale soft nanoimprint lithographic replication of rubbed polyimide substrates to form alignment layers for liquid crystal devices. Systematic studies of the surface relief morphology of the polyimide and molded structures in three different polymers illustrate good lithographic fidelity down to relief heights of several nanometers, and with some capabilities at the level of ∼1 nm. Collective results of experiments with several polymer formulations for molds and molded materials and process conditions indicate that this Molecular-Scale fidelity in replication can be used to produce surfaces that will effectively align liquid crystal molecules. Good electro-optical responses from liquid crystal light modulators that are formed in this manner suggest utility for fundamental studies and potential practical application.
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Molecular-Scale soft imprint lithography for alignment layers in liquid crystal devices
Nano Letters, 2007Co-Authors: Rongsheng Lin, John A RogersAbstract:We describe Molecular-Scale soft nanoimprint lithographic replication of rubbed polyimide substrates to form alignment layers for liquid crystal devices. Systematic studies of the surface relief morphology of the polyimide and molded structures in three different polymers illustrate good lithographic fidelity down to relief heights of several nanometers, and with some capabilities at the level of approximately 1 nm. Collective results of experiments with several polymer formulations for molds and molded materials and process conditions indicate that this Molecular-Scale fidelity in replication can be used to produce surfaces that will effectively align liquid crystal molecules. Good electro-optical responses from liquid crystal light modulators that are formed in this manner suggest utility for fundamental studies and potential practical application.
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polymer imprint lithography with Molecular Scale resolution
Nano Letters, 2004Co-Authors: Anshu Gaur, John A Rogers, Matthew Meitl, Lise Bilhaut, Lolita Rotkina, Jingfeng Wang, Phil Geil, Moonsub Shim, Anne ShimAbstract:We show that small diameter, single-walled carbon nanotubes can serve as templates for performing polymer imprint lithography with feature sizes as small as 2 nm − comparable to the size of an individual molecule. The angstrom level uniformity in the critical dimensions of the features provided by this unusual type of template provides a unique ability to investigate systematically the resolution of imprint lithography at this Molecular Scale. Collective results of experiments with several polymer formulations for the molds and the molded materials suggest that the density of cross-links is an important Molecular parameter that influences the ultimate resolution in this process. Optimized materials enable reliable, repetitive patterning in this single nanometer range.
Nathan D Mcclenaghan - One of the best experts on this subject based on the ideXlab platform.
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Molecular Scale logic gates
Chemistry: A European Journal, 2004Co-Authors: Prasanna A De Silva, Nathan D McclenaghanAbstract:Currently available approaches to Molecular-Scale logic gates are summarized and compared. These include: chemically-controlled fluorescent and transmittance-based switches concerned with small molecules, DNA oligonucleotides with fluorescence readout, oligonucleotide reactions with DNA-based catalysts, chemically-gated photochromics, reversibly denaturable proteins, Molecular machines with optical and electronic signals, two-photon fluorophores and multichromophoric transient optical switches. The photochemical principles of electron and energy transfer are involved in several of these approaches. More complex Molecular logic systems with reconfigurability and superposability provide contrasts with current semiconductor electronics. Integration of simple logic functions to produce more complex ones is also discussed in terms of recent developments.
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Molecular‐Scale Logic Gates
Chemistry: A European Journal, 2004Co-Authors: A. Prasanna De Silva, Nathan D McclenaghanAbstract:Currently available approaches to Molecular-Scale logic gates are summarized and compared. These include: chemically-controlled fluorescent and transmittance-based switches concerned with small molecules, DNA oligonucleotides with fluorescence readout, oligonucleotide reactions with DNA-based catalysts, chemically-gated photochromics, reversibly denaturable proteins, Molecular machines with optical and electronic signals, two-photon fluorophores and multichromophoric transient optical switches. The photochemical principles of electron and energy transfer are involved in several of these approaches. More complex Molecular logic systems with reconfigurability and superposability provide contrasts with current semiconductor electronics. Integration of simple logic functions to produce more complex ones is also discussed in terms of recent developments.
Rongsheng Lin - One of the best experts on this subject based on the ideXlab platform.
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Molecular-Scale soft imprint lithography for alignment layers in liquid crystal devices
Nano Letters, 2007Co-Authors: Rongsheng Lin, John A RogersAbstract:We describe Molecular-Scale soft nanoimprint lithographic replication of rubbed polyimide substrates to form alignment layers for liquid crystal devices. Systematic studies of the surface relief morphology of the polyimide and molded structures in three different polymers illustrate good lithographic fidelity down to relief heights of several nanometers, and with some capabilities at the level of approximately 1 nm. Collective results of experiments with several polymer formulations for molds and molded materials and process conditions indicate that this Molecular-Scale fidelity in replication can be used to produce surfaces that will effectively align liquid crystal molecules. Good electro-optical responses from liquid crystal light modulators that are formed in this manner suggest utility for fundamental studies and potential practical application.
Donald L. Sparks - One of the best experts on this subject based on the ideXlab platform.
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Advances in coupling of kinetics and Molecular Scale tools to shed light on soil biogeochemical processes
Plant and Soil, 2015Co-Authors: Donald L. SparksAbstract:Background Biogeochemical processes in soils such as sorption, precipitation, and redox play critical roles in the cycling and fate of nutrients, metal(loid)s and organic chemicals in soil and water environments. Advanced analytical tools enable soil scientists to track these processes in real-time and at the Molecular Scale. Scope This review focuses on recent research that has employed state-of-the-art Molecular Scale spectroscopy, coupled with kinetics, to elucidate the mechanisms of nutrient and metal(loid) reactivity and speciation in soils. Conclusions By coupling kinetics with advanced Molecular and nano-Scale tools major advances have been made in elucidating important soil chemical processes including sorption, precipitation, dissolution, and redox of metal(loids) and nutrients. Such advances will aid in better predicting the fate and mobility of nutrients and contaminants in soils and water and enhance environmental and agricultural sustainability.
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Advances in coupling of kinetics and Molecular Scale tools to shed light on soil biogeochemical processes
Plant and Soil, 2015Co-Authors: Donald L. SparksAbstract:Background Biogeochemical processes in soils such as sorption, precipitation, and redox play critical roles in the cycling and fate of nutrients, metal(loid)s and organic chemicals in soil and water environments. Advanced analytical tools enable soil scientists to track these processes in real-time and at the Molecular Scale.