Ultrathin Gold Layers Research Articles

Streamlined chemical fixation method for morphological investigation of Candida albicans with scanning electron microscopy

This method describes the preparation of Candida albicans specimen for scanning electron microscopy (SEM), starting from specimen collection to obtaining SEM images. Our approach involves preserving cellular structure and preventing cell degradation through chemical fixation and post-fixation without Osmium tetroxide (OsO4), followed by air dried specimen placed onto Si substrate. Additionally, the method outlines the steps for mounting the prepared specimen onto SEM sample holder aluminum stubs, followed by coating with an ultrathin gold layer via thermal evaporation to enhance specimen/substrate/stub conductivity. The specimens are then mounted in the SEM sample holder. This step-by-step procedure demonstrates successful morphological analysis of C. albicans, providing a comprehensive and effective specimen preparation for SEM analysis.•Effective preparation of Candida albicans specimens for SEM analysis, preserving cellular structure.•Step-by-step specimen mounting and gold coating for enhanced detailed SEM imaging.•Chemical fixation of yeast cells for electron microscopy visualization.

Hyperthermia on colorectal cancer: gold nanoshells-mediated photothermal therapy

Colon cancer or colorectal cancer is one of the most common malignant neoplasms in the world, characterized by uncontrolled cell growth on the colon mucosa. Treatment approaches depend primarily on the characteristics of the tumor´s localization, size, metastasis, and the health status of the patient. Nanomedicine shows itself as a novelty strategy to overcome the limitations of the therapies used in the clinic due to the disregard of the mechanisms associated with multidrug resistance because of the nanometric size of the particles utilized. Gold nanoshells are spheric structures of an approximate size of 30 nm, coated with an ultrathin gold layer that can absorb near-infrared light and convert it to thermal energy to produce hyperthermia on in vivo models of cancer tumors. Nanoparticles-assisted hyperthermia consists of control, direct, and specific heating against the tumor cells by nanoparticle irradiation with an external power source capable of increasing temperature to 39°C - 45°C without damaging surrounding healthy tissue. Compared with other nanomaterials, gold nanoshells show high biocompatibility and low cytotoxicity, which is why adjuvant chemotherapy and hyperthermia on gold nanoshells is a novel and promising approach for the treatment of colorectal cancer.

A High-Sensitivity Bimetallic Grating-Coupled Surface Plasmon Resonance Sensor Based on Two-Dimensional Materials

Optical biosensors based on grating-coupled surface plasmon resonance (GCSPR) technology are an important research topic in the field of bio-photonics. This paper presents a high-performance and high-sensitivity nanostructured bimetallic GCSPR sensor based on two-dimensional materials. When designing the sensor, the sensitivity, full width at half peak (FWHM) and dip strength of the absorption peak (DS) were considered comprehensively, and the comprehensive evaluation parameter FOM+ is defined by making improvements on the basis of figure of merit (FOM). The performance of the sensor can be judged more comprehensively. The performance of the sensor was further improved by optimizing the structure of the sensor. An ultra-thin gold layer was added on the surface of the silver-based GCSPR sensor, which solves the problem of the easy oxidation of silver metal. We tried to coat graphene oxide two-dimensional nanomaterials on the surface of the bimetallic sensor, and the sensitivity and FOM+ of the sensor reached 350 deg/RIU and 473.23, respectively. This is a great improvement compared with the GCSPR sensor in a previous study, and it can be improved at least 74.7%. This sensor can measure a variety of biological molecules and biological cells with high sensitivity and performance by detecting the change in the refractive index of the solution to be measured.

Mechanistic Understanding of Lithium Plating/Stripping Processes on the 3D Conductive Host Based on Vertically Aligned Carbon Nanofibers for Li Metal Anode

The highest theoretical capacity (3860 mAh/g) and lowest redox potential (-3.04 V vs standard hydrogen electrode) makes lithium metal as a promising anode for next generation high energy density batteries.1 Despite theoretical advantages, there are challenges in commercializing Li metal anodes such as low coulombic efficiency, dendrite formation and poor cycling life. Dendrite formation can cause short circuit and thermal runaway, which is a safety concern. Among the various ways to mitigate the Li dendrite formation, using three-dimensional (3D) current collectors with lithiophilic properties and low tortuous pore architecture is an effective way. It would decrease the local current density owing to high active surface area while accommodating the large volume change during prolonged charge/discharge cycles.Vertically aligned carbon nanofibers (VACNF) have been demonstrated as a promising candidate as a lithiophilic 3D host for lithium metal anodes as they possess unique conically stacked lithiophilic graphitic edges with O containing functional groups and high N doping (~6.5 at%).2 However, a fundamental, deeper understanding of the Li plating/stripping processes on such 3D electrodes has not been developed yet. Here in, we investigate the lithium nucleation and growth processes and its morphological changes using ex-situ structural characterization techniques such as SEM and cryo-TEM. The composition of the solid electrolyte interface is investigated using XPS. In-situ Raman spectroscopic studies provided further information about the changes that occur in the VACNFs during Li plating/stripping processes and Li intercalation/deintercalation processes. Ion-beam sputtering of an ultrathin gold layer onto the VACNFs was found to further improve the lithiophilicity of the 3D electrode and lead to more reversible Li metal plating/stripping. The new insights on the electrodeposition of lithium in 3D electrodes and its relationship with the enhanced cycle life acquired using various analytical tools will be discussed.Reference:(1) Manthiram, A.; Chung, S.-H.; Zu, C. Lithium–Sulfur Batteries: Progress and Prospects. Advanced Materials 2015, 27 (12), 1980–2006.(2) Chen, Y.; Elangovan, A.; Zeng, D.; Zhang, Y.; Ke, H.; Li, J.; Sun, Y.; Cheng, H. Vertically Aligned Carbon Nanofibers on Cu Foil as a 3D Current Collector for Reversible Li Plating/Stripping toward High-Performance Li–S Batteries. Advanced Functional Materials 2020, 30 (4), 1906444.

Picosecond acoustics versus tape adhesion test: Confrontation on a series of similar samples with a variable adhesion

A large number of methods have been developed to characterize the adhesion of a thin film to a substrate. Among them, tape test is still one of the most popular methods. Acoustic waves and especially ultra-high frequency acoustic waves are also sensitive to adhesion defects as they affect the way acoustic waves are reflected at such an interface. In this work, we first prepare a series of identical thin-film samples with a variable adhesion at the interface between the film and its substrate. To modulate adhesion of some samples, an ultrathin gold layer is deposited on the substrate before thin-film sputtering. Si+ ion implantation is also used to reinforce locally gold adhesion. The samples are then characterized using two much different techniques: picosecond acoustics (PA) for measuring thickness and acoustic reflection coefficient (R) at the interface and tape test to have an independent evaluation of the adhesion through the peeled area (P). On the samples series, R is found to vary from −0.46 the expected value for a perfectly bonded Ni/Si interface to almost −0.83 not far from −1 which corresponds to delamination. An excellent correlation is found between R and P: high |R| value samples are easily peeled off and P is large. That work demonstrates the capability of PA to perform adhesion test in a totally non-destructive manner and furthermore locally.

Observation of well-defined Kohn-anomaly in high-quality graphene devices at room temperature

Due to its ultra-thin nature, the study of graphene quantum optoelectronics, like gate-dependent graphene Raman properties, is obscured by interactions with substrates and surroundings. For instance, the use of doped silicon with a capping thermal oxide layer limited the observation to low temperatures of a well-defined Kohn-anomaly behavior, related to the breakdown of the adiabatic Born–Oppenheimer approximation. Here, we design an optoelectronic device consisting of single-layer graphene electrically contacted with thin graphite leads, seated on an atomically flat hexagonal boron nitride substrate and gated with an ultra-thin gold layer. We show that this device is optically transparent, has no background optical peaks and photoluminescence from the device components, and no generation of laser-induced electrostatic doping (photodoping). This allows for room-temperature gate-dependent Raman spectroscopy effects that have only been observed at cryogenic temperatures so far, above all the Kohn-anomaly phonon energy normalization. The new device architecture, by decoupling graphene optoelectronic properties from the substrate effects, allows for observing quantum phenomena at room temperature.

Elaboration and characterization of porous ultrathin gold films grown by ion beam assisted deposition

The growth of ultrathin gold layers on a silicon substrate is performed with an unconventional ion beam assisted deposition. In this setup, evaporated gold flow and ion beam flux are perpendicular. 5 and 10 nm thick gold were deposited on tilted samples with the assistance of an argon ion beam at energies of 70 and 150 eV. We explored the evolution of surface morphology, mainly roughness and porosity, with ion bombardment for two gold thicknesses. We have also extrapolated Young’s modulus of these ultrathin layers by means of high-frequency acoustic measurements in the 90–260 MHz range. We also investigated the evolution of wettability of our structures with ion bombardment as well as their electrical and optical responses.

Polarization manipulation of giant photonic spin Hall effect using wave-guiding effect

The enhanced photonic spin Hall effect was previously possible only for the horizontal polarization (H-polarized) in plasmonic systems. The wave-guiding surface plasmonic resonance (SPR) effect is used to report a giant photonic spin Hall effect (G-PSHE) of reflected light for horizontal and vertical polarized waves. This novel work investigated the polarization-manipulated G-PSHE in the modified Kretschmann configuration with an additional glass dielectric thin wave-guiding layer. The ultrathin gold layer and an additional dielectric wave-guiding layer are responsible for achieving millimeter-scale (more than 2 mm to submillimeter) G-PSHE. With this novel approach, polarization manipulation is achieved by employing wave-guiding and the SPR effect. Using a finite element method based simulation study, the impact of an additional thin dielectric wave-guiding layer on G-PSHE is investigated. This study enables the potential application of both horizontal and vertical polarization-based quantum devices and sensors for which light spin plays a pivotal role.

State of the art of ultra-thin gold layers: formation fundamentals and applications.

Fabrication of ultra-thin gold (Au) layers (UTGLs) has been regarded as the key technique to achieve applications with tunable optical response, flexible sensors and electronic devices. Various strategies have been developed to optimize the wetting process of Au, resulting in the formation of UTGLs at a minimum thickness. The related studies on UTGLs attracted huge attention in recent years. On the one hand, the growth processes of UTGLs on different substrates were in-depth probed by advanced in situ characterization techniques and the effects of optimization strategies on the growth of UTGLs were also revealed. On the other hand, based on the understanding of the growth behavior and the assistance of optimization strategies, various applications of UTGLs were realized based on optical/plasmon responses, surface-enhanced Raman scattering and as electrodes for various sensors and electronic devices, as well as being seed layers for thin film growth. In this focused review, both the fundamental and practical studies on UTGLs in the most recent years are elaborated in detail. The growth processes of UTGLs revealed by in situ characterization techniques, such as grazing-incidence small-angle X-ray scattering (GISAXS), as well as the state of the art of UTGL-based applications, are reviewed.

Electrosorptive removal of organic water constituents by positively charged electrically conductive UF membranes

Negatively charged electrically conductive ultrafiltration (UF) membranes have been intensively investigated for fouling mitigation and rejection enhancement in recent years. This study reports the novel approach of applying positive charge (+2.5 V cell potential) to a conductive membrane to induce electrosorption of negatively charged substances onto the membrane. Subsequently, desorption of negatively charged substances is achieved by changing the potential periodically (e.g., after 30 min) to negative charge (-2.5 V cell potential). For this purpose, sputter deposition of ultra-thin gold layers (40 nm) is used to generate electrically conductive gold-polymer-gold flat sheet membranes by coating the active and the support layer of two commercial polymer UF membranes (polyethersulfone UP150, polyamide M5). When M5 membrane was charged positively during filtration (+2.5 V), Suwannee River NOM, Hohloh lake NOM, humic acid and Brilliant Blue ionic dye showed removal rates of 70 %, 75% and 93% and 99%, respectively. Whereas, when no potential was applied (0 V) removal rates were only 1 – 5 %. When a positive potential was applied to the active membrane layer and a negative potential was applied to the support layer (cell potential 2.5 V), a significant increase of flux with 25 L/(m² h) was observed due to the induction of electro-osmosis. Electrosorption was only observed for M5 membrane (ζ: +13 mV, pH 7) and not with UP150 membrane (ζ: -29 mV, pH 7). Due to a low current density of 1.1 A/m² at a flux of 100 L/(m² h), the additional energy consumption of electrosorption and desorption process was low with 0.03 kWh per m³ of permeate. This study delivered the proof of concept for the novel process of electrosorptive UF with energy consumption between microfiltration and ultrafiltration but NOM removal rates of nanofiltration membranes.

Medieval nanotechnology: Thickness determination of Zwischgold samples

• Focused study aiming at technological parameters of corroded Mediaeval Zwischgold. • Gold layer in a nanoscale thickness range of 20–50 nm, with the peak at 30 nm. • Full foil thickness (50–260 nm) obtained from EDX derived Ag/Au weight ratio. • Ultra-high-resolution SEM measurements, supported by STEM and RBS. • Scientific evidence for paleness of Zwischgold. A special gilding material called Zwischgold has been frequently observed in medieval gilded artefacts. As a bilayer metal leaf made from gold and silver, it exhibits similar but slightly paler golden colour tone compared to pure gold. Zwischgold surface can be darkened quickly due to the corrosion of its silver base. Despite its frequent mentions in medieval guild statutes, the production of Zwischgold and its important technological parameters have been under a veil of secrecy since the Middle Ages. Here, we examine the thicknesses and materials proportions of medieval Zwischgold, through high-resolution scanning electron microscopy coupled with energy dispersive X-ray analysis (SEM-EDX) on a large number of samples taken from late medieval gilded sculptures. We observe that medieval Zwischgold contains ultra-thin gold layers in a thickness range of ca. 20–50 nm, indicating the employment of high-precision technologies in manufacturing of delicate art materials in the late medieval period. It further clarifies some ambiguity in gilding history, regarding the colour appearance of medieval Zwischgold. As supportive data, Rutherford backscattering spectrometry (RBS) and scanning transmission electron microscopy (STEM) were applied, in order to confirm the precision and accuracy of the sample preparation and the SEM analysis.

Real-time insight into nanostructure evolution during the rapid formation of ultra-thin gold layers on polymers.

Ultra-thin metal layers on polymer thin films attract tremendous research interest for advanced flexible optoelectronic applications, including organic photovoltaics, light emitting diodes and sensors. To realize the large-scale production of such metal-polymer hybrid materials, high rate sputter deposition is of particular interest. Here, we witness the birth of a metal-polymer hybrid material by quantifying in situ with unprecedented time-resolution of 0.5 ms the temporal evolution of interfacial morphology during the rapid formation of ultra-thin gold layers on thin polystyrene films. We monitor average non-equilibrium cluster geometries, transient interface morphologies and the effective near-surface gold diffusion. At 1 s sputter deposition, the polymer matrix has already been enriched with 1% gold and an intermixing layer has formed with a depth of over 3.5 nm. Furthermore, we experimentally observe unexpected changes in aspect ratios of ultra-small gold clusters growing in the vicinity of polymer chains. For the first time, this approach enables four-dimensional insights at atomic scales during the gold growth under non-equilibrium conditions.

Flexible semitransparent perovskite solar cells with gradient energy levels enable efficient tandems with Cu(In,Ga)Se2

Abstract Flexible semitransparent perovskite solar cells (PVSCs) hold promising applications on buildings and unmanned vehicles with irregular surfaces. Efficient wide-bandgap PVSCs are a determining factor for building perovskite-based tandem cells, in which energy level alignment plays significant roles in reducing nonradiative recombination loss at interfaces. Here, we report on the fabrication of efficient flexible semitransparent wide-bandgap PVSCs with gradient energy level alignments at both electron- and hole-selective contacts. We design a triple-electron-selective contact as electron transport layers with gradient Fermi level alignment with the conduction band of wide-bandgap perovskite, which consists of trans-1,2-Diaminocyclohexane-N,N,N′,N′-tetraacetic (CyDTA), tin dioxide (SnO2), and CyDTA-complexed SnO2. Moreover, an ultrathin gold layer embedded between 2,2′,7,7′-tetrakis(N,N-bis(p-methoxy-phenyl)amino)-9,9′-spirobifluorene (spiro-OMeTAD) hole transport layer and molybdenum oxide protection layer facilitates effective hole transport to the anode. We conduct comprehensive and solid simulation at both charge-selective contacts to reveal the working mechanisms. The champion flexible semitransparent 1.75 eV wide-bandgap PVSC achieves an efficiency of 15.02% with excellent light transparency of around 70% beyond the wavelength of 700 nm, enabling all-flexible perovskite/Cu(In,Ga)Se2 tandem devices with efficiencies beyond 21%.

Approaches for deep-ultraviolet surface plasmon resonance sensors.

Aluminum (Al) is a preferred metal for designing deep-ultraviolet (DUV) surface plasmon resonance (SPR)-based sensors. The native oxide layer (alumina), which grows when the Al film is exposed to air, adds an extra layer to the multilayer stack and consequently affects the DUV-SPR sensing performance. To mitigate the performance loss in DUV-SPR-based sensing, new, to the best of our knowledge, approaches are considered here. We first consider chromium, indium (In), nickel, and platinum as alternative plasmonic materials to Al. In-film-based DUV-SPR sensors exhibit the best performance parameters compared to these alternative materials. We next consider the approach of replacing the native oxide layer by an ultrathin gold (Au) layer on top of bare Al or In. With an optimal Au thickness, higher sensitivity as compared to oxidized metals is observed. The next approach adds one or more graphene layers on top of the bare metal film. In this case, the performance depends on the number of graphene layers, but improvement in sensor characteristics in the DUV is also obtained. The use of Au or graphene overlayers increases the refractive index sensing dynamic range, which can be significant for In with these overlayers under certain operating conditions.

(Invited) Novel Optical Phenomena in Nanoplasmonic Arrays

Extraordinary optical transmission (EOT) through subwavelength-scale hole arrays in metal films, discovered nearly 20 years ago by Ebbesen and co-workers, has spurred intense effort in nano-plasmonics and nano-optics. To date virtually all the measurements in this field have involved intricate hole arrays in metal films fabricated using complex lithography and etching. This results result in structures less than a millimeter square, which necessitates a complex setup of an optical microscope tied to a spectrophotometer for measurements. We describe a far simpler system that exhibits the EOT, that does not require any lithography, and is scalable to large areas, and generate intense optical fields that serve as a platform for novel luminescent phenomena. We experimentally and theoretically demonstrate that a continuous gold film on a periodically textured substrate of nanocup arrays, surprisingly exhibits extraordinary optical transmission, even though no holes were etched in the film.To fabricate nanocup arrays we utilized a polycarbonate master with a periodic array of nanocups (of pitch 750 nm) and replicated the inverse of that pattern to a poly-dimethyl-siloxane (PDMS) elastomer. The PDMS elastomer was then used to nanoimprint the nanocup array on a polystyrene film. A thin non-conformal gold film was sputter-deposited on the polystyrene with angle-directed deposition. Although the gold film was continuous, its thickness varied spatially, with the film being thinnest at the bottom of the nanocup. Optical measurements [1] on the gold-coated nanocup array revealed an extraordinary transmission peak at a wavelength just smaller than the period, with an enhancement of ~2.5 compared to the classically expected value, even though there were no holes in the film. Scattering matrix simulations model well the transmission and reflectance measurements when an ultrathin gold layer (~5 nm), smaller than the skin depth, is retained at the bottom of the nanocups. Electric field intensities are enhanced by >100 within the nanocup. The ultrathin gold layer causes transmission through it with an enhancement of the field intensity by ~40.These arrays are a novel platform for nanoscale luminescent phenomena. Quantum dots embedded within the nanocup arrays show [2] a radiative decay rate that is increased by as much as a factor of 20, from the interaction of the strong optical field with the luminescent quantum dot. In an emerging bio-marker application we demonstrate [3] slowed release rate from medicinal coatings on these nanocups – a feature that could be useful to many emerging drug therapies. Novel metasurfaces of nanocup and nanocone arrays offer a novel platform for nanoplasmonics, nanophotonics, control of light matter interactions, and surface charges [4]. Such nano-arrays hence provide a novel platform for luminescent nano-materials.We acknowledge the financial support from the National Science Foundation through grants CMMI-1265844 and CMMI-170648.1. A. Peer and R. Biswas, Nanoscale 8, 4657 - 4666 (2016).2. A. Peer, Z. Hu, A. Singh, J. A. Hollingsworth, R. Biswas, and H. Htoon, Small 13, 1700660 (2017).3. A. Peer, R. Dhakal, R. Biswas, J. Kim, Nanoscale Patterning of Biopolymers for functional bio-surfaces and controlled drug release, Nanoscale 8, 18654–18664 (2016).4. Q. Li, A. Peer, I. Cho, R. Biswas, J. Kim, Replica molding-based nanopatterning of tribocharge on elastomer with application to electrohydrodynamic nanolithography, Nature Communications 9, 974 (2018). Figure 1

Interface and Reliability Analysis of Au-Passivated Cu–Cu Fine-Pitch Thermocompression Bonding for 3-D IC Applications

Optimally engineered ultrathin gold (Au) layer as an effective surface passivation for low-temperature, low-pressure fine-pitch Cu–Cu bonding is demonstrated in this paper. The Au passivation layer not only performs the role of protecting the underlying Cu surface from unwanted oxidation but it also helps in reducing the effective surface roughness, which are two major requirements for thermocompression bonding. In addition, Au, being a noble metal, ensures efficient surface passivation of Cu even at elevated temperatures. Furthermore, Au-passivated Cu surfaces show significantly high {111}-oriented surface planes with random grain structures at the bonding interface, which account for enhanced diffusion ability. Herein, an optimized Au passivation layer of 3 nm has resulted in high-quality fine-pitch Cu–Cu thermocompression bonding at 140 °C and 0.3-MPa pressure. The bonded samples have further been subjected to various reliability studies in order to confirm the efficacy of the proposed bonding scheme, along with mathematical modeling to cross check using Fick’s second law of approximation. The bonded samples have attributed to a high bond strength (>200 MPa) and a very low and stable specific contact resistance ( $\sim 1.43 \times 10^{\mathrm {-8}}\Omega $ cm $^{2}$ ) under robust conditions, which is significantly better than the values previously reported in the literature.

Flexible Conductors from Brown Algae for Green Electronics

AbstractIn this paper a novel approach is presented to prepare flexible and transparent conducting films, whose components can be separated and recovered via a recycling process. The fabrication method is based on low power sputtering of ultrathin gold layers on sodium alginate free‐standing films. The resulting foils are thin, easy to handle, and shape, while showing good conductive properties. In particular, they show excellent resistance to mechanical stress, like bending or rubbing, and are highly stable in ambient atmosphere over several months. Therefore they may represent a very promising candidate to be employed in green electronics, thanks to the reduced energy consumption required for their fabrication, the absence of toxic components or chemicals that are derived from oil, and the possibility to disassemble the devices at the end of their life in environmentally friendly conditions.

High-Quality Ultrathin Gold Layers with an APTMS Adhesion for Optimal Performance of Surface Plasmon Polariton-Based Devices.

A low-absorption adhesion layer plays a crucial role for both localized and propagating surface plasmons when ultrathin gold is used. To date, the most popular adhesion layers are metallic, namely, Cr and Ti. However, to the best of our knowledge, the influence of these adhesion layers on the behavior of propagating plasmon modes has not been thoroughly investigated nor reported in the literature. It is therefore important to study the effect of these few- to several-nanometers-thick adhesion layers on the propagating plasmons because it may affect the performance of plasmonic devices, in particular, when the Au layer is not much thicker than the adhesion layers. We experimentally compared the performances of the ultrathin gold films to show the pivotal influence of adhesion layers on highly confined propagating plasmonic modes, using Cr and 3-aminopropyl trimethoxysilane (APTMS) adhesion layers and without any adhesion layer. We show that the gold films with the APTMS adhesion layer have the lowest surface roughness and the short-range surface plasmon polaritons supported on the Au surface exhibit properties close to the theoretical calculations, considering an ideal gold film.

Real structure of the ZnO epitaxial films on (0001) leucosapphire substrates coated by ultrathin gold layers

The real structure of ZnO films formed by magnetron sputtering on (0001) leucosapphire substrates coated by an ultrathin (less than 0.7 nm) Au buffer layer has been studied by high-resolution microscopy. It is shown that modification of the leucosapphire substrate surface by depositing ultrathin Au layers does not lead to the formation of Au clusters at the film–substrate interface but significantly improves the structural quality of ZnO epitaxial films. It is demonstrated that the simplicity and scalability of the technique used to modify the substrate surface in combination with a high (above 2 nm/s) film growth rate under magnetron sputtering make it possible to obtain high-quality (0001) ZnO epitaxial films with an area of 5–6 cm2.

Uniform Large-Area Free-Standing Silver Nanowire Arrays on Transparent Conducting Substrates

Arrays of silver nanowires have received increasing attention in a variety of applications such as surface-enhanced Raman scattering (SERS), plasmonic biosensing and electrode for photoelectric devices. However, until now, large scale fabrication of device-suitable silver nanowire arrays on supporting substrates has seen very limited success. Here we show the synthesis of free-standing silver nanowire arrays on indium-tin oxide (ITO) coated glass by pulsed electrodeposition into anodic aluminum oxide (AAO) templates. We use an in situ oxygen plasma cleaning process and a sputtered Ti layer to enhance the adhesion between the template and ITO glass. An ultrathin gold layer (2 nm) is deposited as a nucleation layer for the electrodeposition of silver. An unprecedented high level of uniformity and control of the nanowire diameter, spacing and length has been achieved. The absorption measurements show that the free-standing silver nanowire arrays possess tunable plasmonic resonances.