Fabrication Of Nanostructured Surfaces Research Articles

Rapid fabrication of nanostructured surfaces using nanocoining

A new process for creating high quality ordered arrays of nanofeatures called nanocoining is presented. A diamond die with a structured area of nanofeatures (1600 features in a 20 μm × 20 μm area) is used to physically transfer features to a mold surface. The die is attached to an actuator capable of producing an elliptical tool-path, the dimensions of which are process dependent and enable the die to match velocity with the moving mold during contact to avoid dragging the nanostructured area along the mold surface (smear). Nanocoining process parameters are discussed which enable indents to be indexed precisely to completely cover target areas. Techniques for die alignment and depth control are also required to create large areas (339 mm2) of nanofeatures in short times (∼20 min). Nanocoining experiments were performed at 1 kHz (1000 indents or 1.6 million features per second) on a flat electroless nickel sample. UV curable replicates were then created from the nickel mold and both the mold and replicate were examined in an SEM and AFM.

Electrochemical Fabrication of Nanostructured Surfaces for Enhanced Response

The objective of this work is to explore approaches to enhance electrochemical signals through sequential deposition and capping of gold particles. Gold nanoparticles are electrodeposited from KAuCl(4) solution under potentiostatic conditions on glassy carbon substrates. The number density of the nanoparticles is increased by multiple deposition steps. To prevent secondary nucleation processes, the nanoparticles are isolated after each potentiostatic deposition step by self-assembled monolayers (SAMs) of decanethiol or mercaptoethanol. The increasing number of particles during five deposition/protection rounds is monitored by assembling electroactive SAMs using a ferrocene-labeled alkanethiol. A precise estimation of the surface area of the gold nanoparticles by formation of an oxide layer on gold is difficult due to oxidation of the glassy carbon surface. As an alternative approach, the charge flow of the electroactive SAM is used for surface measurement of the gold surface area. A sixfold increase in the redox signal in comparison to a bulk gold surface is observed, and this increase in redox signal is particularly notable given that the surface area of the deposited nanoparticles is only a fraction of the bulk gold surface. After five rounds of deposition there is a gold loading of 1.94 mug cm(-2) of the deposited nanoparticles as compared to 23.68 mug cm(-2) for the bulk gold surface. Remarkably, however, the surface coverage of the ferrocene alkanethiol on the bulk material is only 10 % of that achieved on the deposited nanoparticles. This enhancement in signal of the nanoparticle-modified surface in comparison to bulk gold is thus demonstrated not to be attributable to an increase in surface area, but rather to the inherent properties of the surface atoms of the nanoparticles, which are more reactive than the surface atoms of the bulk material.

Nano-structured Surface Fabrication for Higher Luminescent LED by Self-assembled Block Copolymer Lithography

Nano-structured Surface Fabrication for Higher Luminescent LED by Self-assembled Block Copolymer Lithography

Fabrication of Nanostructured Surfaces Using Self-Assembled Monolayers

We describe a new method for 3 dimensional nanostructuring on silicon surfaces using self-assembled monolayers. Partial multilayers were formed by repeated deposition of trichlorosilylheptadecanoic acid methyl ester (TSHEME) and subsequent reduction to yield a hydroxylic surface. These structures were afterwards oxidised using UV/ozone, yielding silicon oxide features. In this way both organic multilayered structures as well as ones comprised of silicon oxide have been produced with precise control of the height and invariant lateral shape of these structures. We have tried to apply samples prepared in this fashion to the calibration of AFM-scanners in vertical direction. Due to height artefacts caused by the tip-sample interaction a general calibration is not possible on the molecular scale. However, the structures produced can be used as model systems for the investigation of various sources of height artefacts and also for calibration purposes as long as samples with similar chemical and mechanical properties are to be investigated.

自己組織化による原子スケールテンプレート法を用いた表面ナノ構造の作成

自己組織化による原子スケールテンプレート法を用いた表面ナノ構造の作成

Fabrication of surface nanostructures by scanning tunneling microscope induced decomposition of SiH4 and SiH2Cl2

Nanostructures with lateral dimensions below 10 nm are fabricated on Si(111)7×7 surfaces by scanning tunneling microscope induced dissociation of the precursor gases SiH4 and SiH2Cl2. The molecules are activated between the tunnel tip and the surface, where highly reactive species are produced by the interaction of molecules with free electrons in the tunnel gap. The molecular fragments accumulate directly below the tip and build up the nanostructure. Information on the deposition mechanism that is effective at the onset of deposition is obtained by careful evaluation of the deposition voltage threshold regime.