(1976). Nuclear Tracks in Solids (Principles and Applications) Nuclear Technology: Vol. 30, No. 1, pp. 91-92.

Nuclear Tracks in Solids (Principles and Applications)

Nanostructures have attracted huge interest as a rapidly growing class of materials for many applications. Several techniques have been used to characterize the size, crystal structure, elemental composition and a variety of other physical properties of nanoparticles. In several cases, there are physical properties that can be evaluated by more than one technique. Different strengths and limitations of each technique complicate the choice of the most suitable method, while often a combinatorial characterization approach is needed. In addition, given that the significance of nanoparticles in basic research and applications is constantly increasing, it is necessary that researchers from separate fields overcome the challenges in the reproducible and reliable characterization of nanomaterials, after their synthesis and further process (e.g. annealing) stages. The principal objective of this review is to summarize the present knowledge on the use, advances, advantages and weaknesses of a large number of experimental techniques that are available for the characterization of nanoparticles. Different characterization techniques are classified according to the concept/group of the technique used, the information they can provide, or the materials that they are destined for. We describe the main characteristics of the techniques and their operation principles and we give various examples of their use, presenting them in a comparative mode, when possible, in relation to the property studied in each case.

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Characterization techniques for nanoparticles: comparison and complementarity upon studying nanoparticle properties

A common misconception is that the irradiation of solids with energetic electrons and ions has exclusively detrimental effects on the properties of target materials. In addition to the well-known cases of doping of bulk semiconductors and ion beam nitriding of steels, recent experiments show that irradiation can also have beneficial effects on nanostructured systems. Electron or ion beams may serve as tools to synthesize nanoclusters and nanowires, change their morphology in a controllable manner, and tailor their mechanical, electronic, and even magnetic properties. Harnessing irradiation as a tool for modifying material properties at the nanoscale requires having the full microscopic picture of defect production and annealing in nanotargets. In this article, we review recent progress in the understanding of effects of irradiation on various zero-dimensional and one-dimensional nanoscale systems, such as semiconductor and metal nanoclusters and nanowires, nanotubes, and fullerenes. We also consider the t...

Ion and electron irradiation-induced effects in nanostructured materials

Electrochromics for smart windows: Oxide-based thin films and devices

https://www.szfki.hu/~kamaras/cikkek/Anomalies%20in%20thickness%20measurements%20of%20gr.pdf

Anomalies in thickness measurements of graphene and few layer graphite crystals by tapping mode atomic force microscopy

The radiation damage tracks on the surface of muscovite mica due to single 78.2 MeV 127I ions from the Uppsala EN tandem accelerator have been studied using tapping mode scanning force microscopy (TM-SFM). Conically-shaped hillocks having nearly circular bases were observed on a sample irradiated at normal incidence. Samples irradiated at grazing angles of incidence displayed wider and taller hillocks, and each hillock was accompanied by a raised tail over the bulk ion track. First SFM results are also presented from a study of radiation damage features on mica and single crystals of L-valine induced by single 23 MeV C60 ions from the Orsay tandem accelerator. Brief comments are made on the scaling laws that could link results obtained with atomic and cluster ions.

Radiation damage features on mica and L-valine probed by scanning force microscopy

We present scanning force microscope images of craterlike defects induced by individual 78.2-MeV [sup 127]I ions incident on organic single-crystal [ital L]-valine surfaces. For grazing incidence ions, the craters are elongated along the ion azimuth of incidence and display a raised tail in the surface above the ion track. This permanent plastic deformation of the surface indicates that a hydrodynamic pressure-pulse phenomenon occurs in response to the electronically deposited energy.

Scanning-force-microscopy study of MeV-atomic-ion-induced surface tracks in organic crystals.

Anomalies in Nanostructure Size Measurements by AFM

Even-numbered positive-ion carbon clusters (${\mathrm{C}}_{2\mathit{n}}$, n=20,21,...) are ejected from a solid film of organic polymer---poly(vinylidene difluoride) (PVDF)---when bombarded by MeV atomic ions. Carbon-cluster ions are formed as a result of a single primary-ion impact. The distribution of cluster sizes suggests that the clusters have closed carbon-cage (fullerene) structure. Measurements of the yield and initial-velocity distributions of the ejected cluster ions are performed in a time-of-flight mass spectrometer equipped with an electrostatic ion mirror. The results are compared to data for ions ejected by MeV projectiles from films of synthetic fullerene (${\mathrm{C}}_{60}$ and ${\mathrm{C}}_{70}$) targets. The initial-radial-velocity distribution for cluster ions ejected from the polymer differ markedly from those of synthetic fullerene targets. While ${\mathrm{C}}_{60}$ and ${\mathrm{C}}_{70}$ ions from synthetic fullerene targets have ejection-angle distributions symmetric with respect to the target-surface normal, the mean takeoff angle of carbon-cluster ions ejected from PVDF is off-normal and towards the direction of the incoming primary ion. It is also a clear indication that carbon-cluster ions ejected from PVDF originate in the high-energy-density region created by the fast primary ion. Experiments for establishing the dependence of the carbon-cluster yield Y on the energy loss of the primary ion have been performed. A stronger dependence of the yield for the ${\mathrm{C}}_{60}$ ions desorbed from PVDF targets [Y\ensuremath{\propto}(dE/dx${)}^{3.4}$] than for ions from targets with synthetic ${\mathrm{C}}_{60}$ [Y\ensuremath{\propto}(dE/dx${)}^{2.0}$] has been observed. This supports the conclusion that carbon-cluster ions from PVDF are formed in the axially expanding high-energy-density plasma region.

Formation of fullerenes in MeV-ion sputtering from organic solids.

Anomalies in atomic force microscopy (AFM) based size determination of nanoparticles were studied via comparative analysis of experiments and numerical calculations. Single tungsten oxide nanoparticles with a mean diameter of $3\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ were deposited on mica and graphite substrates and were characterised by AFM. The size (height) of the nanoparticles, measured by tapping mode AFM, was found to be sensitive to the free amplitude of the oscillating tip, thus indicating that the images were not purely topographical. By comparing the experimental results to model calculations, we demonstrate that the dependence of the nanoparticle size on the oscillation amplitude of the tip is an inherent characteristic of the tapping mode AFM; it is also a function of physical properties such as elasticity and surface energy of the nanoparticle and the sample surface, and it depends on the radius of curvature of the tip. We show that good approximation of the real size can easily be obtained from plots of particle height vs free amplitude of the oscillating tip, although errors might persist for individual experiments. The results are valid for size (height) determination of any nanometer-sized objects imaged by tapping mode AFM.

J. Kopniczky

Papers

Radiation damage features on mica and L-valine probed by scanning force microscopy

Scanning-force-microscopy study of MeV-atomic-ion-induced surface tracks in organic crystals.

Anomalies in Nanostructure Size Measurements by AFM

Formation of fullerenes in MeV-ion sputtering from organic solids.

Anomalies in nanostructure size measurements by AFM