8 resultados para MODIFIED GOLD ELECTRODES

em Cambridge University Engineering Department Publications Database


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Carbon nanostructures have been much sought after for cold-cathode field emission applications. Herein a printing technique is reported to controllably nanostructure chemical vapor deposited graphene into vertically standing fins. The method allows for the creation of regular arrays of bilayer graphene fins, with sharp ridges that, when printed onto gold electrodes, afford a new type of field emission electron source geometry. The approach affords tunable morphologies and excellent long term and cyclic stabilities.

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Ferrocene-terminated self-assembled monolayers (Fc-SAMs) are one of the most studied molecular aggregates on metal electrodes. They are easy to fabricate and provide a stable and reproducible system to investigate the effect of the microenvironment on the electron transfer parameters. We propose a novel application for Fc-SAMs, the detection of molecular interactions, based on the modification of the SAM with target-specific receptors. Mixed SAMs were fabricated by coimmobilization on Au electrodes of thiolated alkane chains with three different head groups: hydroxy terminating head group, ferrocene head group, and a functional head group such as biotin. Upon binding, the intrinsic electric charge of the target (e.g., streptavidin) modifies the electrostatic potential at the plane of electron transfer, causing a shift in the formal potential E degrees '. The SAMs were characterized by AC voltammetry. The detection mechanism is confirmed by measurements of formal potential as a function of electrolyte pH.

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FBAR devices with carbon nanotube (CNT) electrodes have been developed withthe aim of taking advantage of the low density and high acoustic impedance ofthe CNTs compared to other known materials. The influence of the CNTs on thefrequency response of the FBAR devices was studied by comparing two identicalsets of devices, one set comprised FBARs fabricated with chromium/gold bilayerelectrodes, and the second set comprised FBARs fabricated with CNT electrodes.It was found that the CNTs had a significant effect on attenuating travellingwaves at the surface of the FBARs membranes due to their high elastic stiffness.Finite element analysis of the devices fabricated was carried out using COMSOLMultiphysics, and the numerical results confirmed the experimental resultsobtained. © 2010 IEEE.

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Film bulk acoustic resonator (FBAR) devices with carbon nanotube (CNT) electrodes directly grown on a ZnO film by thermal chemical vapor deposition have been fabricated. CNT electrodes possess a very low density and high acoustic impedance, which reduces the intrinsic mass loading effect resulting from the electrodes' weight and better confines the longitudinal acoustic standing waves inside the resonator, in turn providing a resonator with a higher quality factor. The influence of the CNTs on the frequency response of the FBAR devices was studied by comparing two identical sets of devices; one set comprised FBARs fabricated with chromium/ gold bilayer electrodes, and the second set comprised FBARs fabricated with CNT electrodes. It was found that the CNTs had a significant effect on attenuating traveling waves at the surface of the FBARs' membranes because of their high elastic stiffness. Three-dimensional finite element analysis of the devices fabricated was carried out, and the numerical simulations were consistent with the experimental results obtained. © 2011 IEEE.