Search results for "Scanning probe"
showing 10 items of 55 documents
Solution and on-surface synthesis of structurally defined graphene nanoribbons as a new family of semiconductors.
2018
Graphene nanoribbons (GNRs) with various structures and properties can be synthesized in solution or on surface.
Polycyclic aromatic chains on metals and insulating layers by repetitive [3+2] cycloadditions
2020
The vast potential of organic materials for electronic, optoelectronic and spintronic devices entails substantial interest in the fabrication of π-conjugated systems with tailored functionality directly at insulating interfaces. On-surface fabrication of such materials on non-metal surfaces remains to be demonstrated with high yield and selectivity. Here we present the synthesis of polyaromatic chains on metallic substrates, insulating layers, and in the solid state. Scanning probe microscopy shows the formation of azaullazine repeating units on Au(111), Ag(111), and h-BN/Cu(111), stemming from intermolecular homo-coupling via cycloaddition reactions of CN-substituted polycyclic aromatic az…
Scanning Probe Microscopy Study of the Metal-Rich Layered Chalcogenides TaM2Te2 (M = Co, Ni)
1998
The compounds TaNi2Te2 and TaCo2Te2 have been examined by scanning tunneling and atomic force microscopy. The title phases crystallize in layered structures with metal slabs sandwiched by tellurium atoms. Scanning probe microscope images of the surfaces of these materials arise from the surface tellurium atoms anddepending on the experimental conditionscan show very different features. The images have been simulated through surface charge densities calculated within the Extended Huckel and LMTO frameworks.
Scanning probe microscopy of pine and birch kraft pulp fibres
2000
Abstract Fibres of the conventional pine and birch kraft pulps were characterized by scanning probe microscopy (SPM). The surface characteristics of these pulps taken at the early stages of pulping were compared with those from later stages of pulping (with or without subsequent oxygen/alkali delignification). It was observed that during delignification a granular surface structure was replaced by a fibrillar surface containing various disruptions. The granular and fibrillar regions were particularly well resolved by using phase imaging in tapping mode of SPM. It was concluded that the granular structure corresponded to surface lignin since the decrease in the relative amount of the granula…
<title>Metallic and semiconducting nanowires: properties and architectures</title>
2003
Nanowires are expected to play an important role in future electronic, optical devices and nanoelectromechanical devices. Measuring the electrical and mechanical properties of nanowires is however a difficult task due to their small dimensions. Here we report the use of an in-situ microscopy technique, which combines transmission electron microscopy (TEM) with scanning probe microscopy (SPM), to investigate the electrical and mechanical properties of metallic and semiconductor nanowires. Additionally, in this paper we describe a novel approach for synthesizing mesoporous silicas with tunable pore diameters, wall thickness and pore spacings that can be used as tempates for the assembly of se…
Smart High-κ Nanodielectrics Using Solid Supported Polyoxometalate-Rich Nanostructures
2011
Utilizing Langmuir-Blodgett deposition and scanning probe microscopy, we have investigated the extent to which cations alter the self-assembly processes of hybrid polyoxometalates (POMs) on surfaces. The well-defined 2D hexagonal nanostructures obtained were extensively characterized and their properties were studied, and this has revealed fascinating dielectric behavior and reversible capacitive properties. The nanostructures are extremely stable under ambient conditions, and yet exhibit fascinating self-patterning upon heating. These findings present POMs as effective smart nanodielectrics and open up a new field for future POM applications. (c) 2011 American Chemical Society.
Near-field study with a photon scanning tunneling microscope: Comparison between dielectric nanostructure and metallic nanostructure
2007
Abstract Scanning near-field optical microscopy (SNOM) integrates standard optical methods with scanning probe microscopy (SPM) techniques allowing to collect optical information with resolution well beyond the diffraction limit. We study the influence on image formation of several parameters in scanning near-field microscopy. The numerical calculations have been carried out using the differential method. We investigate a 2D-PSTM configuration with a dielectric rectangular object. We will focus on the collection type SNOM in a constant height scanning mode. Various oscillation patterns are observed from both sides of the nanostructure, which we interpret as interference between the diffract…
Near-field observation of evanescent light wave coupling in subwavelength optical waveguides
2002
International audience; We report the observation, in the range of visible frequencies, of the coupling of light into integrated waveguides of subwavelength cross-sections together with a subwavelength detection at the output, of such guides. Coupling in is produced by controlling the focusing of a laser beam totally reflected at the surface of the sample. Several tens of micrometres long dielectric ridges have been efficiently excited with this technique. The phenomenon is observed in direct space by a Photon Scanning Tunneling Microscope which also allows to test the principle of detection in a subwavelength volume.
Atomic Force Microscopy and Spectroscopy
2021
Atomic force microscopy (AFM) is probably the most celebrated technique falling into the family of experimental methods known as scanning probe microscopy. AFM is primarily designed to obtain the morphology of the surface of a solid material by using the force of interaction between an inert probe and the sample. The AFM microscope can generally be operated in many ways for morphology investigations, but they can be roughly classified into two main groups: static- and dynamic-deflection modes. Since atomic force microscopy makes use of tip-surface interaction to reconstruct the surface morphology of materials, it is of fundamental importance to fully understand the nature and properties of …
Imaging of photonic nanopatterns by scanning near-field optical microscopy
2002
We define photonic nanopatterns of a sample as images recorded by scanning near-field optical microscopy with a locally excited electric dipole as a probe. This photonic nanopattern can be calculated by use of the Green’s dyadic technique. Here, we show that scanning near-field optical microscopy images of well-defined gold triangles taken with the tetrahedral tip as a probe show a close similarity to the photonic nanopattern of this nanostructure with an electric dipole at a distance of 15 nm to the sample and tilted 45° with respect to the scanning plane.