Open Access. Powered by Scholars. Published by Universities.®

Nanoscience and Nanotechnology Commons

Open Access. Powered by Scholars. Published by Universities.®

PDF

Gold

Discipline
Institution
Publication Year
Publication
Publication Type

Articles 1 - 20 of 20

Full-Text Articles in Nanoscience and Nanotechnology

Electrodeposited Semiconductor Nanostructures & Epitaxial Thin Films For Flexible Electronics, Naveen Kumar Mahenderkar Jan 2018

Electrodeposited Semiconductor Nanostructures & Epitaxial Thin Films For Flexible Electronics, Naveen Kumar Mahenderkar

Doctoral Dissertations

"Single-crystal Si is the bedrock of semiconductor devices due to the high crystalline perfection which minimizes electron-hole recombination, and the dense native silicon oxide which minimizes surface states. To expand the palette of electronic materials beyond planar Si, an inexpensive source of highly ordered material is needed that can serve as an inert substrate for the epitaxial growth of grain boundary-free semiconductors, photonic materials, and superconductors. There is also a need for a simple, inexpensive, and scalable fabrication technique for the growth of semiconductor nanostructures and thin films. This dissertation focuses on the fabrication of semiconducting nanowires (polycrystalline Ge & …


Gold Nanoparticle Colorimetric Sensing Technology, Eve Borden May 2016

Gold Nanoparticle Colorimetric Sensing Technology, Eve Borden

Nanoscale Science & Engineering (discontinued with class year 2014)

No abstract provided.


Investigation Of The Optical And Sensing Characteristics Of Nanoparticle Arrays For High Temperature Applications, Gnanaprakash Dharmalingam Jan 2016

Investigation Of The Optical And Sensing Characteristics Of Nanoparticle Arrays For High Temperature Applications, Gnanaprakash Dharmalingam

Legacy Theses & Dissertations (2009 - 2024)

The monitoring of polluting gases such as CO and NOx emitted from gas turbines in power plants and aircraft is important in order to both reduce the effects of such gases on the environment as well as to optimize the performance of the respective power system. The need for emissions monitoring systems is further realized from increased regulatory requirements that are being instituted as a result of the environmental impact from increased air travel. Specifically, it is estimated that the contributions from aircraft emissions to total NOx emissions will increase from 4% to 17% between 2008 and 2020. Extensive fuel …


In Vitro Studies Of Gold And Gold Silica Nanoparticle Radiosensitization With Kilovoltage X-Rays, Gregory Colarch May 2015

In Vitro Studies Of Gold And Gold Silica Nanoparticle Radiosensitization With Kilovoltage X-Rays, Gregory Colarch

UNLV Theses, Dissertations, Professional Papers, and Capstones

Technological advances in the ability to construct and manipulate nanoscale particles have opened up the possibility of using solid metallic nanoparticles and mixed metal nanoshells as a means to increase dose enhancement and treatment efficacy to tumors. In order for nanoparticles to be an effective form of treatment, they must be delivered to tumors in sufficient concentrations so that there is a dose enhancement factor due to ionizing radiation, as well as being essentially non-toxic to healthy cells. Gold nanoparticles and silica-gold nanoshells fit these requirements. Gold has a high atomic number (Z=79), which gives a larger cross section for …


Metal-Assisted Etching Of Silicon Molds For Electroforming, Ralu Divan, Dan Rosenthal '14, Karim Ogando, Leonidas E. Ocola, Daniel Rosenmann, Nicolaie Moldovan Sep 2013

Metal-Assisted Etching Of Silicon Molds For Electroforming, Ralu Divan, Dan Rosenthal '14, Karim Ogando, Leonidas E. Ocola, Daniel Rosenmann, Nicolaie Moldovan

Student Publications & Research

Ordered arrays of high-aspect-ratio micro/nanostructures in semiconductors stirred a huge scientific interest due to their unique one-dimensional physical morphology and the associated electrical, mechanical, chemical, optoelectronic, and thermal properties. Metal-assisted chemical etching enables fabrication of such high aspect ratio Si nanostructures with controlled diameter, shape, length, and packing density, but suffers from structure deformation and shape inconsistency due to uncontrolled migration of noble metal structures during etching. Hereby the authors prove that a Ti adhesion layer helps in stabilizing gold structures, preventing their migration on the wafer surface while not impeding the etching. Based on this finding, the authors demonstrate …


Negative Index Metamaterials Based On Metal-Dielectric Nanocomposites For Imaging Applications, L. Menon, W. T. Lu, A. L. Friedman, S. P. Bennett, D. Heiman, S. Sridhar Oct 2012

Negative Index Metamaterials Based On Metal-Dielectric Nanocomposites For Imaging Applications, L. Menon, W. T. Lu, A. L. Friedman, S. P. Bennett, D. Heiman, S. Sridhar

Srinivas Sridhar

Negative index metamaterials are demonstrated based on metal-dielectric nanocomposites prepared using a versatile bottom-up nanofabrication approach. The method involves the incorporation of vertically aligned metal nanowires such as Au and Ag inside dielectric aluminum oxide nanotemplates. Optical absorbance measurements show resonance peaks corresponding to the transverse and longitudinal surface plasmon modes. A quantitative model based on effective medium theory is in excellent agreement with experimental data, and points to specific composite configurations and wavelength regimes where such structures can have applications as negative refraction media for imaging.


Negative Index Metamaterials Based On Metal-Dielectric Nanocomposites For Imaging Applications, L. Menon, W. T. Lu, A. L. Friedman, S. P. Bennett, D. Heiman, S. Sridhar Oct 2012

Negative Index Metamaterials Based On Metal-Dielectric Nanocomposites For Imaging Applications, L. Menon, W. T. Lu, A. L. Friedman, S. P. Bennett, D. Heiman, S. Sridhar

Donald Heiman

Negative index metamaterials are demonstrated based on metal-dielectric nanocomposites prepared using a versatile bottom-up nanofabrication approach. The method involves the incorporation of vertically aligned metal nanowires such as Au and Ag inside dielectric aluminum oxide nanotemplates. Optical absorbance measurements show resonance peaks corresponding to the transverse and longitudinal surface plasmon modes. A quantitative model based on effective medium theory is in excellent agreement with experimental data, and points to specific composite configurations and wavelength regimes where such structures can have applications as negative refraction media for imaging.


Negative Index Metamaterials Based On Metal-Dielectric Nanocomposites For Imaging Applications, L. Menon, W. T. Lu, A. L. Friedman, S. P. Bennett, D. Heiman, S. Sridhar Oct 2012

Negative Index Metamaterials Based On Metal-Dielectric Nanocomposites For Imaging Applications, L. Menon, W. T. Lu, A. L. Friedman, S. P. Bennett, D. Heiman, S. Sridhar

Latika Menon

Negative index metamaterials are demonstrated based on metal-dielectric nanocomposites prepared using a versatile bottom-up nanofabrication approach. The method involves the incorporation of vertically aligned metal nanowires such as Au and Ag inside dielectric aluminum oxide nanotemplates. Optical absorbance measurements show resonance peaks corresponding to the transverse and longitudinal surface plasmon modes. A quantitative model based on effective medium theory is in excellent agreement with experimental data, and points to specific composite configurations and wavelength regimes where such structures can have applications as negative refraction media for imaging.


Super-Resolution Imaging Using A Three-Dimensional Metamaterials Nanolens, B. D. F. Casse, W. T. Lu, Y. J. Huang, E. Gultepe, L. Menon, S. Sridhar Oct 2012

Super-Resolution Imaging Using A Three-Dimensional Metamaterials Nanolens, B. D. F. Casse, W. T. Lu, Y. J. Huang, E. Gultepe, L. Menon, S. Sridhar

Latika Menon

Super-resolution imaging beyond Abbe's diffraction limit can be achieved by utilizing an optical medium or "metamaterial" that can either amplify or transport the decaying near-field evanescent waves that carry subwavelength features of objects. Earlier approaches at optical frequencies mostly utilized the amplification of evanescent waves in thin metallic films or metal-dielectric multilayers, but were restricted to very small thicknesses (⪡λ, wavelength) and accordingly short object-image distances, due to losses in the material. Here, we present an experimental demonstration of super-resolution imaging by a low-loss three-dimensional metamaterial nanolens consisting of aligned gold nanowires embedded in a porous alumina matrix. This composite …


Directed Assembly Of Gold Nanoparticle Nanowires And Networks For Nanodevices, Xugang Xiong, Ahmed A. Busnaina, Selvapraba Selvarasah, Sivasubramanian Somu, Ming Wei, Joey Mead, Chia-Ling Chen, Juan Aceros, Prashanth Makaram, Mehmet R. Dokmeci Apr 2012

Directed Assembly Of Gold Nanoparticle Nanowires And Networks For Nanodevices, Xugang Xiong, Ahmed A. Busnaina, Selvapraba Selvarasah, Sivasubramanian Somu, Ming Wei, Joey Mead, Chia-Ling Chen, Juan Aceros, Prashanth Makaram, Mehmet R. Dokmeci

Sivasubramanian Somu

Alternating electric field is used to assemble gold nanoparticle nanowires from liquid suspensions. The effects of electrode geometry and the dielectrophoresis force on the chaining and branching of nanowire formation are investigated. The nanowire assembly processes are modeled using finite element calculations, and the particle trajectories under the combined influence of dielectrophoresis force and viscous drag are simulated. Nanoparticle nanowires with 10 nm resolution are fabricated. The wires can be further oriented along an externally introduced flow. This work provides an approach towards rapid assembly and organization of ultrasmall nanoparticle networks.


Structure And Optical Properties Of Self-Assembled Multicomponent Plasmonic Nanogels, Tao Cong, Satvik N. Wani, Peter Anthony Paynter, Radhakrishna Sureshkumar Jul 2011

Structure And Optical Properties Of Self-Assembled Multicomponent Plasmonic Nanogels, Tao Cong, Satvik N. Wani, Peter Anthony Paynter, Radhakrishna Sureshkumar

Biomedical and Chemical Engineering - All Scholarship

Multicomponent plasmonic nanogels (PNGs) capable of broadband absorption of light in the 400-700 nm wavelength range were synthesized by the self-assembly of metal nanoparticles with wormlike surfactant micelles. Small angle x-ray scattering and rheological experiments suggest that the nanoparticles bridge micelle fragments to aid the formation a stable gel phase with exceptional color uniformity. Their optical absorbance could be robustly tuned by changing the nanoparticle type (Au/Ag), size, shape, and/or concentration. The PNGs have relatively low viscosity and are thermoreversible. Potential applications to the manufacturing of coatings and interfaces for solar energy harvesting and reconfigurable optical devices can be envisioned.


Three Dimensional Controlled Assembly Of Gold Nanoparticles Using A Micromachined Platform, Nishant Khanduja, Selvapraba Selvarasah, Chia-Ling Chen, Mehmet R. Dokmeci, Xugang Xiong, Prashanth Makaram, Ahmed A. Busnaina Jun 2011

Three Dimensional Controlled Assembly Of Gold Nanoparticles Using A Micromachined Platform, Nishant Khanduja, Selvapraba Selvarasah, Chia-Ling Chen, Mehmet R. Dokmeci, Xugang Xiong, Prashanth Makaram, Ahmed A. Busnaina

Ahmed A. Busnaina

By using optical lithographic procedures, the authors present a micromachined platform for large scale three dimensional (3D) assembly of gold nanoparticles with diameters of ∼ 50 nm. The gold nanoparticles are formed into 3D low resistance bridges (two terminal resistance of ∼ 40 Ω) interconnecting the two microelectrodes using ac dielectrophoresis. The thickness of the parylene interlevel dielectric can be adjusted to vary the height of the 3D platform for meeting different application requirements. This research represents a step towards realizing high density, three dimensional structures and devices for applications such as nanosensors, vertical integration of nanosystems, and characterization of …


Directed Assembly Of Gold Nanoparticle Nanowires And Networks For Nanodevices, Xugang Xiong, Ahmed A. Busnaina, Selvapraba Selvarasah, Sivasubramanian Somu, Ming Wei, Joey Mead, Chia-Ling Chen, Juan Aceros, Prashanth Makaram, Mehmet R. Dokmeci Jun 2011

Directed Assembly Of Gold Nanoparticle Nanowires And Networks For Nanodevices, Xugang Xiong, Ahmed A. Busnaina, Selvapraba Selvarasah, Sivasubramanian Somu, Ming Wei, Joey Mead, Chia-Ling Chen, Juan Aceros, Prashanth Makaram, Mehmet R. Dokmeci

Ahmed A. Busnaina

Alternating electric field is used to assemble gold nanoparticle nanowires from liquid suspensions. The effects of electrode geometry and the dielectrophoresis force on the chaining and branching of nanowire formation are investigated. The nanowire assembly processes are modeled using finite element calculations, and the particle trajectories under the combined influence of dielectrophoresis force and viscous drag are simulated. Nanoparticle nanowires with 10 nm resolution are fabricated. The wires can be further oriented along an externally introduced flow. This work provides an approach towards rapid assembly and organization of ultrasmall nanoparticle networks.


Directed Assembly Of Gold Nanoparticle Nanowires And Networks For Nanodevices, Xugang Xiong, Ahmed A. Busnaina, Selvapraba Selvarasah, Sivasubramanian Somu, Ming Wei, Joey Mead, Chia-Ling Chen, Juan Aceros, Prashanth Makaram, Mehmet R. Dokmeci May 2011

Directed Assembly Of Gold Nanoparticle Nanowires And Networks For Nanodevices, Xugang Xiong, Ahmed A. Busnaina, Selvapraba Selvarasah, Sivasubramanian Somu, Ming Wei, Joey Mead, Chia-Ling Chen, Juan Aceros, Prashanth Makaram, Mehmet R. Dokmeci

Mehmet R. Dokmeci

Alternating electric field is used to assemble gold nanoparticle nanowires from liquid suspensions. The effects of electrode geometry and the dielectrophoresis force on the chaining and branching of nanowire formation are investigated. The nanowire assembly processes are modeled using finite element calculations, and the particle trajectories under the combined influence of dielectrophoresis force and viscous drag are simulated. Nanoparticle nanowires with 10 nm resolution are fabricated. The wires can be further oriented along an externally introduced flow. This work provides an approach towards rapid assembly and organization of ultrasmall nanoparticle networks.


Three Dimensional Controlled Assembly Of Gold Nanoparticles Using A Micromachined Platform, Nishant Khanduja, Selvapraba Selvarasah, Chia-Ling Chen, Mehmet R. Dokmeci, Xugang Xiong, Prashanth Makaram, Ahmed A. Busnaina May 2011

Three Dimensional Controlled Assembly Of Gold Nanoparticles Using A Micromachined Platform, Nishant Khanduja, Selvapraba Selvarasah, Chia-Ling Chen, Mehmet R. Dokmeci, Xugang Xiong, Prashanth Makaram, Ahmed A. Busnaina

Mehmet R. Dokmeci

By using optical lithographic procedures, the authors present a micromachined platform for large scale three dimensional (3D) assembly of gold nanoparticles with diameters of ∼ 50 nm. The gold nanoparticles are formed into 3D low resistance bridges (two terminal resistance of ∼ 40 Ω) interconnecting the two microelectrodes using ac dielectrophoresis. The thickness of the parylene interlevel dielectric can be adjusted to vary the height of the 3D platform for meeting different application requirements. This research represents a step towards realizing high density, three dimensional structures and devices for applications such as nanosensors, vertical integration of nanosystems, and characterization of …


Synthesis, Stabilization, And Characterization Of Metal Nanoparticles, Gregory White Ii Dec 2010

Synthesis, Stabilization, And Characterization Of Metal Nanoparticles, Gregory White Ii

All Dissertations

Wet chemical synthesis techniques offer the ability to control various nanoparticle characteristics including size, shape, dispersibility in both aqueous and organic solvents, and tailored surface chemistries appropriate for different applications. Large quantities of stabilizing ligands or surfactants are often required during synthesis to achieve these nanoparticle characteristics. Unfortunately, excess reaction byproducts, surfactants, and ligands remaining in solution after nanoparticle synthesis can impede application, and therefore post-synthesis purification must be employed. A liquid-liquid solvent/anti-solvent pair (typically ethanol/toluene or ethanol/hexane for gold nanoparticles, GNPs) can be used to both purify and size-selectively fractionate hydrophobically modified nanoparticles. Alternatively, carbon dioxide may be used …


Effect Of Particle Properties And Light Polarization On The Plasmonic Resonances In Metallic Nanoparticles, U. Guler, R. Turan Jul 2010

Effect Of Particle Properties And Light Polarization On The Plasmonic Resonances In Metallic Nanoparticles, U. Guler, R. Turan

U. Guler

The resonance behavior of localized surface plasmons in silver and gold nanoparticles was studied in the visible and near-infrared regions of the electromagnetic spectrum. Arrays of nano-sized gold (Au) and silver (Ag) particles with different properties were produced with electron-beam lithography technique over glass substrates. The effect of the particle size, shape variations, period, thickness, metal type, substrate type and sulfidation were studied via transmission and reflectance measurements. The results are compared with the theoretical calculations based on the DDA simulations performed by software developed in this study. We propose a new intensity modulation technique based on localized surface plasmons …


Preparation And Catalytic Activity Of Nanostructured Pd And Au-Pd Thin Films, Cui-Cui Qiu, Jin-Tao Zhang, Fang Tian, Hou-Yi Ma May 2008

Preparation And Catalytic Activity Of Nanostructured Pd And Au-Pd Thin Films, Cui-Cui Qiu, Jin-Tao Zhang, Fang Tian, Hou-Yi Ma

Journal of Electrochemistry

The nanostructured Pd thin films were directly formed on the glassy carbon electrode(GCE) substrates by using potential cycling method.The as-prepared Pd thin films deposited onto the GCE were able to absorb enough amount of hydrogen in acidic solutions at the cathodic potentials more negative than the hydrogen evolution potential.Moreover,the absorbed hydrogen could be used as the reducing agent to reduce gold(III) ions to Au nanoclusters,thereby forming bimetallic Au-Pd thin films on the GCE substrate.SEM and cyclic voltammetry characterization demonstrated that the Au-Pd thin films display much higher catalytic activity towards the electro-oxidation of ethanol than the pure Pd thin films.


Photothermal Reshaping Of Prismatic Au Nanoparticles In Periodic Monolayer Arrays By Femtosecond Laser Pulses, Wenyu Huang, Wei Qian, Mostafa A. El-Sayed Jan 2005

Photothermal Reshaping Of Prismatic Au Nanoparticles In Periodic Monolayer Arrays By Femtosecond Laser Pulses, Wenyu Huang, Wei Qian, Mostafa A. El-Sayed

Wenyu Huang

Prismatic goldnanoparticles in the periodic monolayer arrays prepared with nanosphere lithography technique can be reshaped with femtosecond laser pulses at different powers and wavelengths. As the power density of 400 nm femtosecond laser increases, the prismatic particle tips begin to round and the overall particle shape changes from a prism to a sphere with a tripodal intermediate. The formation of the tip-rounded nanoprisms is probably due to the dewetting properties of gold on quartz surface and the low melting temperature at the tips. The formation of the tripodal nanoparticles is attributed to the inhomogeneous heating and lattice rearrangement of the …


Preparation And Application Of Gold_Film On The Surface Of Bacterial_Modified Carbon Paste Electrode, Rongzong Hu, Yanping Ruan, Hao Xu, Jinkun Fu, Weide Zhang, Wenyun Hu May 1999

Preparation And Application Of Gold_Film On The Surface Of Bacterial_Modified Carbon Paste Electrode, Rongzong Hu, Yanping Ruan, Hao Xu, Jinkun Fu, Weide Zhang, Wenyun Hu

Journal of Electrochemistry

A novel method for preparation of gold_film composed of ultra_fine gold particles was reported in this paper. The gold_film was prepared by electrochemical method on the surface of the paste electrode modified with the strain Bacillus sp. D01 which has strong ability to absorb and reduce Au3+. In addition, this paper reported an experimental method of determining trace amount of Cu2+ in water solution using cathodic stripping analysis to estimate the performances of the obtained gold_film. The experimental results indicated that this new method for preparation of gold_film is simple. The obtained gold_film electrode is stable and sensitive to determining …