Evolution of Ion Beam Synthesized Au Nanoclusters in SiO2 under Ion Irradiation

2000 ◽  
Vol 647 ◽  
Author(s):  
Bernd Schmidt ◽  
Karl-Heinz Heinig ◽  
Arndt Mücklich
Keyword(s):  
Size Distribution ◽  
Ostwald Ripening ◽  
Ion Irradiation ◽  
Kinetic Monte Carlo ◽  
Ion Beam ◽  
Thick Layer ◽  
High Energy ◽  
Au Nanoclusters ◽  
Post Irradiation ◽  
Mean Size

AbstractThe evolution of the mean size and the size distribution of Au nanoclusters (NCs) under high-energy ion irradiation has been studied. Au NCs were synthesized in a 480 nm thick SiO2 layer by 330 keV Au+ implantation and subsequent annealing at T = 1000 °C for 1h in dry O2. XTEM images show a 70 nm thick layer of Au NCs, being centered at the projected ion range Rp(330keV) = 100 nm, having a mean NC size of 5 nm at Rp, and resembling the broad Lifshiz-Slyozov-Wagner (LSW) size distribution of diffusion controlled Ostwald ripening. Post-irradiation of the Au NCs by 4.5 MeV gold ions was used in order to tailor their size and size distribution. The high-energy Au+ irradiations were performed at 190...210 °C with a fluence of (0.5...1.0)×1016 cm-2. By the post-irradiation no gold was deposited into the SiO2 layer, the Au+ ions come to rest in the (001)Si substrate at Rp(4.5MeV) = 1 [.proportional]m. XTEM images of the post-irradiated Au NCs show a strong decrease of their mean size as well as the width of their size distribution. The observed NC evolution under ion irradiation agrees with recent theoretical predictions and kinetic Monte-Carlo simulations.

Electron and ion irradiation-induced dissolution of mechanical twins in the intermetalic U3Si: An in situ HVEM study

1989 ◽  
Vol 47 ◽  
pp. 652-653
Author(s):  
Charles W. Allen ◽  
Robert C. Birtcher
Keyword(s):  
Elevated Temperatures ◽  
Ion Irradiation ◽  
Ion Beam ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Heavy Ion ◽  
High Energy ◽  
Mechanical Twinning ◽  
In Situ Experiments

The uranium silicides, including U3Si, are under study as candidate low enrichment nuclear fuels. Ion beam simulations of the in-reactor behavior of such materials are performed because a similar damage structure can be produced in hours by energetic heavy ions which requires years in actual reactor tests. This contribution treats one aspect of the microstructural behavior of U3Si under high energy electron irradiation and low dose energetic heavy ion irradiation and is based on in situ experiments, performed at the HVEM-Tandem User Facility at Argonne National Laboratory. This Facility interfaces a 2 MV Tandem ion accelerator and a 0.6 MV ion implanter to a 1.2 MeV AEI high voltage electron microscope, which allows a wide variety of in situ ion beam experiments to be performed with simultaneous irradiation and electron microscopy or diffraction.At elevated temperatures, U3Si exhibits the ordered AuCu3 structure. On cooling below 1058 K, the intermetallic transforms, evidently martensitically, to a body-centered tetragonal structure (alternatively, the structure may be described as face-centered tetragonal, which would be fcc except for a 1 pet tetragonal distortion). Mechanical twinning accompanies the transformation; however, diferences between electron diffraction patterns from twinned and non-twinned martensite plates could not be distinguished.

scholarly journals Hydrophilicity Improvement of Polymer Surfaces Induced by Simultaneous Nuclear Transmutation and Oxidation Effects Using High-Energy and Low-Fluence Helium Ion Beam Irradiation

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2770
Author(s):  
Jung Woo Kim ◽  
Seung Hwa Yoo ◽  
Young Bae Kong ◽  
Sung Oh Cho ◽  
Eun Je Lee
Keyword(s):  
Surface Texture ◽  
Ion Irradiation ◽  
Ion Beam ◽  
High Energy ◽  
Contact Angles ◽  
Polymer Chains ◽  
Polymer Surfaces ◽  
Water Contact ◽  
Chemical Structures ◽  
Nuclear Transmutation

Two commodity polymers, polystyrene (PS) and high-density polyethylene (HDPE), were irradiated by high-energy He ion beams at low fluence to examine the wettability changes at different fluences. The water contact angles of the PS and HDPE surfaces were reduced from 78.3° to 46.7° and 81.5° to 58.5°, respectively, upon increasing the fluence from 0 to 1 × 1013 He2+/cm2 for irradiation durations ≤4 min. Surface analyses were performed to investigate these wettability changes. Surface texture evaluations via scanning electron and atomic force microscopies indicated non-remarkable changes by irradiation. However, the chemical structures of the irradiated polymer surfaces were notable. The high-energy He ions induced nuclear transmutation of C to N, leading to C–N bond formation in the polymer chains. Further, C–O and C=O bonds were formed during irradiation in air because of polymer oxidation. Finally, amide and ester groups were generated by irradiation. These polar groups improved hydrophilicity by increasing surface energies. Experiments with other polymers can further elucidate the correlation between polymer structure and surface wettability changes due to high-energy low-fluence He ion irradiation. This method can realize simple and effective utilization of commercial cyclotrons to tailor polymer surfaces without compromising surface texture and mechanical integrity.

Anisotropic Strain – Anisotropic Heating Engineering for Silicon Nanocrystals in SiO2

2009 ◽  
Vol 156-158 ◽  
pp. 523-528 ◽  
Author(s):  
I.V. Antonova ◽  
D.V. Marin ◽  
Vladimir A. Volodin ◽  
V.A. Skuratov ◽  
J. Jedrzejewski ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Size Distribution ◽  
Silicon Nanocrystals ◽  
Ion Irradiation ◽  
Ion Bombardment ◽  
High Energy ◽  
Optical And Electrical Properties ◽  
Anisotropic Strain ◽  
Si Nanocrystals ◽  
New Si

In the present paper we discuss effects due to high-energy ion bombardment of SiO2 layers with embedded Si nanocrystals (NCs), such as the formation of new Si NCs in such layers, amorphization of previously existing NCs, modification of NC size distribution, and modification of optical and electrical properties of NCs. These effects are identified as resulting from anisotropic strain - anisotropic heating in NCs-SiO2 layers under ion irradiation.

Physics Mechanisms Involved in the Formation and Recrystallization of Amorphous Regions in Si through Ion Irradiation

2008 ◽  
Vol 139 ◽  
pp. 71-76 ◽  
Author(s):  
Iván Santos ◽  
Luis Alberto Marqués ◽  
Lourdes Pelaz ◽  
Pedro Lopez ◽  
María Aboy
Keyword(s):  
Molecular Dynamics ◽  
Ion Irradiation ◽  
Kinetic Monte Carlo ◽  
Ion Beam ◽  
Beam Current ◽  
Formation Mechanisms ◽  
Computationally Efficient ◽  
Simulation Tools ◽  
Multi Scale ◽  
Scale Modeling

We focus this work on multi-scale modeling of the ion-beam-induced amorphization and recrystallization in Si, although our scheme can be applied to other materials. We use molecular dynamics to study the formation mechanisms of amorphous regions. We have observed that along with energetic ballistic collisions that generate Frenkel pairs, low energy interactions can produce damage through the melting and quenching of target regions. By quantifying these results, we have developed an improved binary collision approximation model which gives a damage description similar to molecular dynamics. We have successfully applied our model to ion and cluster implantations. In order to define the energetic of defects in a more computationally efficient Kinetic Monter Carlo code, we have used molecular dynamics results related to the recrystallization behavior of local amorphous regions. The combination of all these simulation tools, molecular dynamics (fundamental studies of damage formation and recrystallization), improved binary collisions (including ballistic and melting-related damage) and Kinetic Monte Carlo (for efficient defect kinetics modeling during the implantation and the subsequent annealing), allows us to model the effect of ion mass, beam current and implant temperature on the amount and morphology of residual defects in Si.

Comparison of Conductivity Produced in Polymers and Carbon Films by Pyrolysis and High Energy Ion Irradiation

1983 ◽  
Vol 27 ◽  
Author(s):  
T. Venkatesan ◽  
R. C. Dynes ◽  
B. Wilkens ◽  
A. E. White ◽  
J. M. Gibson ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Carbon Film ◽  
Physical Nature ◽  
High Energy ◽  
Carbon Films ◽  
Chemical Degradation ◽  
Beam Irradiation ◽  
Ion Beam Irradiation

ABSTRACTThe electrical properties of pyrolyzed polymers have been studied recently.1,2 It has been shown that organic, polymeric3 and non-polymeric4 films can be made conductive (ρ ~ 10−3Ωcm) by ion beam irradiation. Common to all of the films was the presence of carbon as a constituent element and both pyrolysis and ion beam irradiation3 was shown to increase the relative carbon content of the films. The ion beam irradiated organic films 3,4 exhibited a temperature dependence of their resistivity of the form ρ(T) = ρ∞e−(TЛ)*, where ρ is the ion-induced resistivity, ρ∞ and T0 are constants and T is the temperature. At very high doses of irradiation (1017cm−2Ar+@ 2MeV) the film resistivity was temperature independent. Very similar transport properties were observed in the pyrolyzed polymers1 as well, though the lowest resistivities achieved were higher than the resistivity values observed in the ion irradiated3 polymer films. In both the pyrolysis and ion-irradiation experiments the temperature dependence has been explained by a model due to Sheng and Abeles,5 which involves charge transport by hopping between conducting islands embedded in an insulating matrix. Such striking similarities between two distinctly different modes of energy deposition in the films, prompted us to compare the effects of pyrolysis and ion irradiation in different carbon containing films. We compared both a polymer (HPR-204°) and a film of electron beam evaporated carbon film. While in the former case one would observe chemical degradation as well as structural modification, by studying pure carbon films the physical nature of the processes could be clarified. We report metallic carrier densities in both films and evidence for significant structural rearrangement. We conclude that pyrolysis and ion beam irradiation have similar effects on both polymer and carbon films.

MODIFICATION OF GROWTH MODE OF Ge ON Si BY PULSED LOW-ENERGY ION-BEAM IRRADIATION

2004 ◽  
Vol 03 (01n02) ◽  
pp. 19-27 ◽  
Author(s):  
A. V. DVURECHENSKII ◽  
J. V. SMAGINA ◽  
V. A. ZINOVYEV ◽  
S. A. TEYS ◽  
A. K. GUTAKOVSKII ◽  
...  
Keyword(s):  
Surface Defect ◽  
Kinetic Monte Carlo ◽  
Ion Beam ◽  
Three Dimensional ◽  
High Energy ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Growth Modes ◽  
Transmission Electron ◽  
Critical Film Thickness

Scanning tunneling microscopy (STM) and reflection high-energy electron diffraction (RHEED) experiments were performed to study growth modes induced by hyperthermal Ge + ion action during molecular beam epitaxy (MBE) of Ge on Si (100). The continuous and pulsed ion beams were used. These studies have shown that ion-beam bombardment during heteroepitaxy leads to decrease in critical film thickness for transition from two-dimensional (2D) to three-dimensional (3D) growth modes, enhancement of 3D island density and narrowing of island size distribution, as compared with conventional MBE experiments. The crystal perfection of Ge / Si structures with Ge islands embedded in Si was analyzed by Rutherford backscattering/channeling technique (RBS) and transmission electron microscopy (TEM). The results of Kinetic Monte Carlo (KMC) simulation have shown that two mechanisms of ion beam action can be responsible for stimulation of 2D–3D transition. They are: (1) surface defect generation by ion impacts and (2) enhancement of surface diffusion.

Radiation-induced disordering and amorphization—An in situ HVEM study of uranium silicide with comparison to natural processes in zirconolite

1990 ◽  
Vol 48 (4) ◽  
pp. 534-535
Author(s):  
R. C. Birtcher ◽  
L. M. Wang ◽  
C. W. Allen ◽  
R. C. Ewing
Keyword(s):  
Electron Irradiation ◽  
Ion Irradiation ◽  
Ion Beam ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Heavy Ion ◽  
High Energy ◽  
In Situ Tem ◽  
In Situ Experiments

We present here results of in situ TEM diffraction observations of the response of U3Si and U3Si2 when subjected to 1 MeV electron irradiation or to 1.5 MeV Kr ion irradiation, and observations of damage occuring in natural zirconolite. High energy electron irradiation or energetic heavy ion irradiation were performed in situ at the HVEM-Tandem User Facility at Argonne National Laboratory. In this Facility, a 2 MV Tandem ion accelerator and a 0.6 MV ion implanter have been interfaced to a 1.2 MeV AEI high voltage electron microscope. This allows a wide variety of in situ experiments to be performed with simultaneous ion irradiation and conventional transmission electron microscopy. During the electron irradiation, the electron beam was focused to a diameter of about 2 μ.m at the specimen thin area. The ion beam was approximately 2 mm in diameter and was uniform over the entire specimen. With the specimen mounted in a heating holder, the temperature increase indicated by the furnace thermocouple during the ion irradiation was typically 8 °K.

Ion Beam Assisted Quantum well Intermixing

1995 ◽  
Vol 396 ◽  
Author(s):  
R. D. Goldberg ◽  
I. V. Mitchell ◽  
S. Charbonneau ◽  
P. Poole ◽  
E. S. Koteles ◽  
...  
Keyword(s):  
Quantum Well ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Multiple Quantum Well ◽  
High Energy ◽  
Multiple Quantum ◽  
Active Components ◽  
Quantum Well Structures ◽  
Ion Species ◽  
Made In

AbstractSignificant progress has been made in the past year in the use of high energy (MeV) ion irradiation to tune the bandgap and therefore emission wavelengths of single and multiple quantum well structures. These shifts are attributable to compositional mixing across the well and barrier layer interfaces, a process that is driven by the vacancy flux, released during the anneal stage, from radiation defects. We present data from a series of measurements in both GaAs- and InP-based QW structures to demonstrate the importance of the implantation parameters chosen (ion species, energy, flux, fluence and implant temperature). The dramatic difference in the response of these two systems with regard to the implant depth is believed to be associated with the very different diffusivities of the Gp III site vacancies. Prospects for implementing the irradiation approach as a spatially selective, planar process in integrated optoelectronic circuitry look very attractive and are illustrated for both passive and active components by reference to recent results from tuned wavelength lasers.

Radiation-Induced Nanostructures in an Iron Phosphate Glass

2003 ◽  
Vol 792 ◽  
Author(s):  
K. Sun ◽  
T. Ding ◽  
L.M. Wang ◽  
R.C. Ewing
Keyword(s):  
Phosphate Glass ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Dose Range ◽  
Iron Phosphate ◽  
High Energy ◽  
High Dose ◽  
Beam Irradiation ◽  
Ion Beam Irradiation ◽  
Feo Nanoparticles

ABSTRACTElectron and ion irradiation-induced nanostructures in an iron phosphate glass with a composition of 45 mol%Fe2O3-55 mol%P2O5 have been characterized by advanced electron microbeam techniques. Analysis by energy-filtered transmission electron microscopy indicated that Fe-rich and P-rich nanophases were formed when the glass was irradiated under a broad (with a diameter of 1.2μm) electron beam [give the dose range]. Phase separation developed with the increase in electron dose (from 1.0×1026e/m2 to 4.8×1026e/m2) as a result of the formation of an Fe-rich phase and pure P-phase. The formation of the Fe-rich and the P-phases are thought to be due to mainly ionization process. Under a low energy ion beam irradiation, Fe/FeO nanoparticles were formed, as confirmed by selected-area electron diffraction analysis. However, no nanoparticles were observed under a high-energy high-dose ion irradiation. The ion beam-irradiation results suggest that the formation of the Fe/FeO nanoparticles was due to preferential sputtering during ion irradiation and that the nanoparticles lie within the surface layers of the glass.

THE USE OF MARKERS AND NUCLEAR MICROANALYSIS TO MONITOR ATOMIC TRANSPORT INDUCED BY ION BOMBARDMENT IN SOLIDS

1995 ◽  
Vol 09 (03n04) ◽  
pp. 163-186 ◽  
Author(s):  
LIONEL THOMÉ ◽  
FRÉDÉRICO GARRIDO
Keyword(s):  
Ion Irradiation ◽  
Ion Beam ◽  
Ion Bombardment ◽  
High Energy ◽  
Near Surface ◽  
Energetic Ions ◽  
Nuclear Microanalysis ◽  
Atomic Transport ◽  
Very High Energy ◽  
Marker Profile

This paper describes an original methodology developed to study the atomic transport in a solid target bombarded with energetic ions. This methodology is based on the use of heavy marker atoms introduced in the near-surface layer of the investigated target and the analysis via nuclear microanalysis techniques of the modifications of the marker profile due to ion bombardment. Results obtained in the case of low- or medium-energy (<10 keV/u ) ion irradiation, leading to the well-known ion-beam-mixing process induced by nuclear elastic collisions, are reported in the first part. The second part deals with the less-investigated case of very-high-energy (>1 MeV/u ) ion irradiation, where a dramatic plastic deformation mechanism induced by electronic excitation has been recently discovered.

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