reec2016 program booklet - research school of physics … booklet.pdf · adepartment of physics and...

2016Internationalworkshopon

Radiation Effects

under

Extreme Conditions

TheAustralianNationalUniversity,Canberra,Australia

26-28October,2016

ProgramandAbstracts

Conferencechairs:RobElliman,ANUPatrickKluth,ANUCormacCorr,ANUThe technical talks, morning and afternoon tea and lunches will be in the Canberry and Springbank rooms (Building 132, Rooms 1.71 and 1.73) in the Crawford Building (see map)The BBQ and Tours will be in RSPE South, (Building 60), Mills Road (see map)

Program:

Tuesday-October25

16:00-18:00WelcomeReception

Wednesday-October26

8:50-9:20RegistrationandCoffee

9:20ConferenceOpening

Session1:Materialsunderextremeirradiation-Chair:TBA

9:30-10:00M.Nastasi(inv.)

IrradiationTolerantAmorphousSiliconOxycarbideandCrystallineFe

Nanocomposites

10:00-10:20T.Tran(cont.)

Tin-hyperdopedgermaniumandthermalstabilityofgermanium–tinalloys

10:20-10:40DISCUSSION

10:40-11:10Morningtea

Session2:Swiftheavyions-Chair:TBA

11:10-11:40W.Weber(inv.)

CharacterizationofIonTrackMorphologyandPropertiesusingAdvanced

ElectronMicroscopyandComputationalTechniques

11:40-12:10F.Djurabekova(inv.)

Moleculardynamicsimulationsoftheimpactofswiftheavyionsonsolids


12:30-14:00Lunch

Session3:AdvancedFacilities/TechniquesI-Chair:TBA

14:00-14:30S.E.Donnelly(inv.)

MIAMI*-2:ANewIn-SituIon-Accelerator/TransmissionElectronMicroscope

FacilityintheUK

14:30-14:50P.Kluth(cont.)

Smallanglex-rayscatteringtostudyswiftheavyiondamageinextreme

environments


15:10-15:40Afternoontea

Session4:AdvancedFacilities/TechniquesII-Chair:TBA

15:40-16:10T.Schenkel(inv.)

Intense,pulsedionbeamstoaccessradiationeffectsunderextremeconditionsat

BerkeleyLab

16:10-16:30A.Xu(cont.)

Micro-tensileTestingofNuclearMaterials


17:30-20:00BBQandtours

Thursday-October27Session5:Plasmafacingmaterials-Chair:TBA

9:00-9:30E.Bernard(inv.)

Tungstenasaplasma-facingmaterialsinfusiondevices:behaviorunderhelium

high-temperatureirradiation

9:30-10:00R.Doerner(inv.)

Plasma-MaterialInteractionsduringburning-plasmarelevantconditions

10:30-11:00M.Thompson(inv.)

Usinggrazing-incidencesmall-angleX-rayscatteringtomeasurehelium-induced

modificationinmetalsexposedtolowtemperatureplasma



Session6:Nanomaterials/HighaspectratiostructuresI–Chair:TBA

11:20-11:50M.E.Toimil-Molares(inv.)

Micro-andNanostructuresfabricatedbyion-tracktechnologyandtheir

exposuretohigh-energysub-psPWclasslasers

11:50-12:20F.Chen(inv.)

ModulationofPhotoluminescenceEmissionsinRare-IonDopedLaserCrystals

byIonImplantedEmbeddedNanoparticles

12:20-12:40K.Nordlund(cont.)

Mechanismofswift-heavyioninducednanoparticleelongationaboveandbelow

thetrackformationthreshold


13:00-14:30Lunch

19:00-22:00Conferencedinner

Friday-October28Session7:AdvancedFacilities/TechniquesIII–Chair:TBA

9:30-10:00A.Vantomme(inv.)

Latticelocationofimplantedimpuritiesbyemissionchanneling:

electricalandmagneticdopantsingroup-IIInitridesandZnO

10:00-10:30E.Wendler(inv.)

Quasiin-situlow-temperatureionimplantationandRBSdefectanalysis:

Technicalrequirements,challengesandapplications

10:30-10:50D.Riley(cont.)

ComplementaryMethodsofTechnicalAnalysis



Session8:Nanomaterials/HighaspectratiostructuresII–Chair:TBA

11:40-12:00A.Hadley(cont.)

Iontracketchednanoporemembranescharacterizedbysmallanglex-ray

scattering

12:00-12:20J.England(cont.)

UnderstandingtheProcessingofThreeDimensionalSemiconductorNano-

DevicesusingTRI3DYN

12:20-12:40H.Alkhaldi(cont.)

TheanalysisofnanoporesinGeionimplantedGeandSi1-xGexalloys


13:00-14:30Conferenceconcludesandlightlunch

Abstracts

Irradiation Tolerant Amorphous Silicon Oxycarbide and Crystalline Fe

Nanocomposites

Michael Nastasi

Director, Nebraska Center for Energy Sciences Research

Elmer Koch Professor, Department of Mechanical and Materials Engineering

University of Nebraska-Lincoln

A major challenge to developing materials with radically extended performance limits at

irradiation extremes will require designing and perfecting atom- and energy- efficient synthesis

of revolutionary new materials that maintain their desired properties while being driven very far

from equilibrium. We examined the radiation tolerance of amorphous silicon oxycarbide (SiOC)

and crystalline Fe nanocomposites. Our research shows that amorphous SiOCs are extremely

stable even under irradiations to 20 dpa at 600 oC. Nanocomposites of these materials with

crystalline Fe are also extremely stable. Characterization shows neither sign of point defect

clusters in Fe layers, nor an indication of crystallization or new phase formation in SiOC layers.

Our findings suggest that the crystalline/amorphous interface and Fe grain boundaries can help to

annihilate point defects generated during irradiation, and therefore enhance radiation tolerance

properties. This presentation will focus on these and other results and their implications.

Tin-hyperdoped germanium and thermal stability of germanium – tin alloys

Tuan T. Tran, Hemi H. Gandhi 2, David Pastor 2, Michael J. Aziz 2 and J. S. Williams 1

1 Department of Electronic Materials Engineering, Research School of Physics and Engineering, Australian National University, Canberra, ACT 0200,

Australia

2 Harvard John A. Paulson School of Engineering and Applied Sciences, Cambridge, Massachusetts, 02138, USA

Ge-Sn alloy is a group IV semiconductor which shows many valuable properties such as high

carrier mobility, truly direct bandgap and fully compatibility with current silicon technology.

As a material for front-end-of-line components such as transistors, studies have shown that

the electron and hole mobility of Ge-Sn alloys can increase by a factor of 4 at Sn

concentrations around ~11% 1. Lasing from a Ge-Sn alloy has also been demonstrated

experimentally 2. Due to the low solid solubility of Sn in Ge lattice, highly Sn concentrated

alloy has to be prepared by non-equilibrium techniques, such as molecular beam epitaxy and

chemical vapor deposition.

It is shown in this presentation that a Ge-Sn alloy with high crystal quality can be fabricated

by ion implantation followed by pulsed laser melting in a range of low implant dose

( ). At high implant doses, a capping layer of silicon dioxide deposited prior

to the implantation can greatly enhance the Sn concentration and the crystal quality of the

material. A single crystalline Ge-Sn alloy of 9 at.%Sn has been achieved by this method. The

data is confirmed by Rutherford backscattering spectroscopy, Raman spectroscopy and

transmission electron microscopy. Finally, data show that the material is stable under

annealing up to 400oC for 30 min, which is in very good agreement with the alloys prepared

by other methods such as molecular beam epitaxy and chemical vapour deposition 3.

1 J. D. Sau and M. L. Cohen, Physical Review B 75, 045208 (2007). 2 S. Wirths, R. Geiger, N. v. d. Driesch, G. Mussler, T. Stoica, S. Mantl, Z. Ikonic,

M. Luysberg, S. Chiussi, J. M. Hartmann, H. Sigg, J. Faist, D. Buca, and D. Grützmacher, Nat Photon 9, 88 (2015).

3 R. Chen, Y.-C. Huang, S. Gupta, A. C. Lin, E. Sanchez, Y. Kim, K. C. Saraswat, T. I. Kamins, and J. S. Harris, Journal of Crystal Growth 365, 29 (2013).

Characterization of Ion Track Morphology and Properties using Advanced

Electron Microscopy and Computational Techniques

W.J. Webera,b, R. Sachanb, E. Zarkadoulab, D.S. Aidhyb, M.F. Chisholmb and Y. Zhangb a Materials Science & Engineering Department, University of Tennessee,

Knoxville, TN 37996, USA. b Materials Science & Technology Division, Oak Ridge National Laboratory,

Oak Ridge TN 37831, USA.

The structure and properties of nanoscale ion tracks created by fast ions in complex oxides

with the pyrochlore structure are investigated. High angle annular dark field imaging,

complemented with molecular dynamics simulations, show that the atoms in the shell

structure surrounding the amorphous core of the track in Gd2Ti2O7 are disordered and have

relatively larger cation-cation interspacing, suggesting the presence of tensile strain [1]. Static

pair-potential calculations show that planar tensile strain lowers the oxygen vacancy

migration barriers, leading to enhanced oxygen ion conductivity in the strained shell structure.

Subsequent irradiation of ion tracks in Yb2Ti2O7 with a nanoscale electron beam can induce

local restructuring of the ion tracks, indicating that locally controlled electron beam

irradiation can be used to further modify the strain and properties of ion tracks. These results

suggest that strain engineering could be used to the tailor transport properties of ion tracks. In

Gd2TiZrO7, dramatic radial variations in ion track size are observed, as large as 40% along

incremental track lengths of ~20 nm. These large variations are speculated to occur due to

differences in ionic radii, local strain effects, and the stochastic competition among Gd, Ti,

and Zr to occupy or not occupy the cation site in the defect-fluorite structure during

recrystallization of the track. These results have been confirmed by molecular dynamics.

This work was supported by the U.S. Department of Energy, Office of Science, Basic Energy

Sciences, Materials Sciences and Engineering Division.

[1] D. S. Aidhy, R. Sachan, E. Zarkadoula, O. H. Pakarinen, M. F. Chisholm, Y. Zhang, and

W. J. Weber, Scientific Reports 5, 16297 (2015).

Molecular dynamic simulations of the impact of swift heavy ions on solids

F. Djurabekovaa, H. Vázquez Muíños, A.A. Leinoa,b, O.H. Pakarinena, K. Nordlunda a Department of Physics and Helsinki Institute of Physics, The University of Helsinki,

Helsinki, Fnland. bOak Ridge National Laboratory, Oak Ridge, Teneessee, USA.

Molecular dynamics (MD) simulation methods have proven to be very insightful concerning

the nature of radiation damage in solids caused by ions with energies < MeV/amu. In this

range of energies, ions lose their energy preferentially in nuclear collisions. Iterative solution

of Newton equations for each atom in the system within MD allows to follow the atomic

displacements of all energetic atoms in atomic cascades until the energy of all atoms is

thermally equilibrated. The functional form describing the interatomic interactions –

interatomic potential - is a keystone of the method and requires a special attention and

motivation for its choice. While simulation of radiation damage produced in collisional

cascades is straightforward, this is not the case for ions with energies greater than 1

MeV/amu. Interaction with electronic subsystem in this energy regime cannot be ignored

anymore, since it is a driving force for the damage seen in experiments as a signature of swift

heavy ion (SHI) interactions with insulators.

Since MD follows the motion of atoms independently on how the energy was introduced in

the system, we apply the MD method also to analyze the mechanisms of damage production

by ions of very high energies, which barely interact with atomic nuclei but lose their energy

on interaction with electrons. In the presentation, several methods of how SHI impact can be

introduced into an MD simulation cell will be presented and discussed. A special attention

will be paid to the parameterization of the models, describing the possibilities and limitations

of modern methods to construct a model avoiding the use of free parameters.

Several examples of application of different models of SHI impacts on 2D and 3D materials

will be given and discussed in details. We also analyze the mechanisms of void formation in

amorphous germanium at low and high SHI fluences.

MIAMI*-2: A New In-Situ Ion-Accelerator / Transmission Electron

Microscope Facility in the UK

S.E. Donnelly, J.A. Hinks and G. Greaves

School of Computing and Engineering

University of Huddersfield, UK.

The original Microscope and Ion Accelerator for Materials Investigation instrument [1] (now

MIAMI-1) began operating in 2010 at the University of Salford before moving to the

University of Huddersfield in 2011. It has now been joined by a new, state-of-the-art

MIAMI-2 facility funded by the United Kingdom’s Engineering and Physical Science

Research Council (EPSRC). The new system incorporates a Hitachi H-9500 300 kV

transmission electron microscope (TEM). This includes a bespoke additional section to the

column which gives line-of-sight access for the ion beams to the specimen in its normal

position between the pole-pieces of the objective lens. On the ion-beam side, MIAMI-2

includes two ion accelerators: a 350 kV NEC machine for self- and heavy-ion irradiation and

a low energy (1–20 keV) Colutron system to provide beams of the light ions helium and

hydrogen. The system thus permits simultaneous, dual-ion irradiation, and a primary focus of

research is the simulation, with ion beams, of neutron damage (including build-up of

transmutation gases) in potential nuclear materials. But research relevant to other extreme

environments such as that of space is also underway, facilitated by a range of heating and

cooling holders permitting irradiation at temperatures ranging from 100–1600 K. The TEM

also includes a differentially pumped specimen region with four accurately controllable gas

inlet jets. Finally, analysis is provided by means of a Gatan Imaging Filter (GIF) and a Bruker

energy-dispersive X-ray spectroscopy system, providing information on the elemental

composition and electronic structure of materials and changes to these under ion irradiation.

Examples will be presented of recent work using the original MIAMI-1 system, together

with preliminary results that highlight the extended capabilities of the new facility.

[1] J.A. Hinks, J.A. van den Berg and S.E. Donnelly J. Vac. Sci. Technol. A 29 (2011) p021003

*Microscopes and Ion Accelerators for Materials Investigations

Small angle x-ray scattering to study swift heavy ion damage in extreme

environments

Patrick Klutha a Research School of Physics and Engineering, The Australian National University,

Canberra, Australia.

For many applications, the stability and evolution of ion tracks in high pressure, high

temperature and corrosive environments are of considerable interest. However, analysis of ion

tracks under these conditions presents significant experimental challenges, as analytical

methods such as transmission electron microscopy are not feasible. Synchrotron based small

angle x-ray scattering (SAXS) enables the study of ion tracks in a variety of sample

environments such as diamond anvil cells (DACs) or high temperature furnaces in situ to

address these challenges.

The presentation will demonstrate the capabilities we devolved over the last years to study the

stability and annealing of ion tracks in minerals under high pressure conditions, the track

annealing kinetics and temperature dependent elastic response of ion tracks in quartz, and

show first in situ measurements of ion track etching in polymers.

Intense, pulsed ion beams to access radiation effects under extreme

conditions at Berkeley Lab

Thomas Schenkel

Accelerator Technology and Applied Physics Division,

Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA

Advances in induction-type ion accelerators and in laser-plasma acceleration have

made intense, short ion pulses available for materials research. With short ion pulse

durations, pump-probe type studies on the dynamics of radiation effects become possible [1,

2]. With pulse durations shorter than the hydrodynamic expansion time of a sample (~sample

thickness / speed of sound, e. g. about 1 ns for a 3 micron thick gold foil with 3000 m/s speed

of sound), intense ion pulses can also heat samples to temperatures >0.5 eV with ion pulse

fluences in excess of a few J/cm2 [3]. This enables studies of transient warm dense matter

states and measurements of the equation of state of materials under conditions of high

temperature and pressure, as they pertain e. g. to the interior of large planets. Further, intense,

short ion pulses emerge as a new tool to locally drive phase transitions in materials, where

phases with desired properties can be stabilized when rapid electronic excitation and heating

are followed by rapid quenching. This promises a path to extend the reach of ion beam

processing for the optimization of materials properties, e. g. for niche applications [4]. In my

talk I will describe our research with intense, pulsed ion beams at Berkeley Lab, where we use

the NDCX-II induction-type ion accelerator and the rapidly developing pulsed ion beam

capabilities at the BELLA-i petawatt laser facility [5].

Acknowledgments: This work was supported by the Office of Science of the US Department

of Energy under contract DE-AC02–05CH11231.

[1] T. Schenkel, et al., Nucl. Instr. Meth. B 315, 350 (2013).

[2] P. Seidl, et al., Journal of Physics: Conference Series 717, 012079 (2016).

[3] J. J. Barnard, et al., Nucl. Inst. Meth. A 733, 45 (2013).

[4] A. Bienfait, et al., Nature 531, 74, (2016).

[5] Q. Ji, et al., Proceedings of the International Particle Accelerator Conference,

IPAC2016, Busan, Korea,

http://accelconf.web.cern.ch/AccelConf/ipac2016/papers/thpmr004.pdf

Micro-tensile Testing of Nuclear Materials

A. Xu*, D. Bhattacharyya

*, M. Ionescu

*, T. Wei

*, G. Thorogood

*, C. Yang

*, L. Edwards

*, G.

Triani*

* Australian Nuclear Science & Technology Organisation, Locked Bag 2001, Kirrawee DC,

Sydney, NSW 2232, Australia

Ni alloy is the material of choice for withstanding the harsh operating conditions within the

reactor pressure vessel of current and future designs of nuclear fission reactors. Yet, little is

still known about the effect of radiation damage which can have detrimental effects on its

mechanical properties. Understanding such changes in mechanical properties from irradiation

is crucial to predicting the lifetime of Ni based structural components within nuclear fission

reactors and ensuring its safe operation. Ion irradiation has become widely accepted as a fast

and economically efficient means of simulating anticipated neutron damage and is used in this

study on Ni alloys. However, the damage depth from ion irradiation is at best 10-20µm which

is too shallow to allow for macro-scale testing of mechanical property changes from radiation.

In this study, we present a novel technique of micro-tensile testing which has been developed

at ANSTO and overcomes the issue of shallow radiation damage depth. This presentation

highlights the unique and versatile capability of micro-tensile testing in studying effect of

radiation on mechanical properties. The first part of this presentation considers effect of strain

rate on tensile deformation behavior of irradiated and unirradiated Ni single crystals. The

single crystal samples are pulled in tension along <100> and <110> directions. Furthermore,

we compare the bulk tensile strength of an ultra-fine-grained Ni-3wt%SiC alloy with the

tensile strength as determined from micro-tensile testing methods. Finally, micro-tensile

samples were machined along grain boundaries and within grains in a Ni super alloy to

compare the changes in mechanical strength pre and post irradiation.

Tungsten as a plasma-facing materials in fusion devices: behavior under

helium high-temperature irradiation

E. Bernarda, R. Sakamotob , N. Yoshidac , C. Grisoliaa, A. Kreterd, M.F. Barthee, R. Bissonf,

M. Thompsong and C. Corrg a IRFM, CEA Cadarache, France.

b National Institute for Fusion Science, Toki, Japan. c Kyushu University, Fukuoka, Japan.

d Forschungszentrum Jülich GmbH, Jülich, Germany. e CEMHTI, CNRS, Orléans, France.

f PIIM, Aix Marseille University, Marseille, France. g Australian National Laboratory, Canberra, Australia.

Choice of plasma-facing materials for next generation fusion machines, such as ITER and

DEMO, is strongly related to the intensive fluxes of light elements, such as He and H

isotopes, which the first wall materials will be subjected to. This irradiation can let to

important damages at the surface, affecting the properties and life span of the materials, hence

the efficiency of the reactor. For W, one of the most promising candidates [1], incident He

particles can drastically affect the surface, with observed formation of dislocation loops,

bubbles or W-fuzz [2].

One key parameter to examine in this aim is the material temperature: indeed, W operation

temperature in fusion can reach up to 1000 ºC. Temperature affects vacancy and interstitial

mobility in the material, and preliminary studies in laboratory highlighted that has a strong

impact on the final micro structure of the material.

We will present our study of helium impact on tungsten and its consequences for the material

properties, with various irradiation setups, and high temperature irradiation as the main

parameter of interest. A dedicated temperature controlled material probe designed for the

exposure of W samples to He plasma in the LHD (Large Helical Device) allows the study of

the material micro structure change in a fusion machine, i.e. in a complex exposure spectra

closer to the ones in future machines such as ITER and DEMO. Various laboratory devices

from ion beam irradiation (Kyushu University, CAMITER) to plasma machine exposure (PSI-

2) completed the study with an extended range and more controlled conditions, hence

providing reference samples to the complex LHD set of conditions.

TEM (Transmission Electron Microscopy) analysis was the main technique used to evaluate

the impact of He irradiation under high temperatures on W microstructure; in particular,

bubbles were observed much deeper than the heavily damaged surface layer, rising concerns

about the consequences for the material properties conservation. This technique was coupled

with Positron Annealing Spectroscopy (PAS) to map the material defects at a lower scale and

Grazing Incidence Small Angle X-ray Scattering (GISAXS) for bubble mapping at a larger

scale. To investigate potential additional trapping due to the material change, deuterium ion

implantation was performed on pre He exposed samples and TDS (Thermo Desorption

Spectrometry) analysis led to evaluate the hydrogen retention. The impact of surface change

on material hardness was also investigated through nano-indentation measurements, giving an

insight on what He irradiation could mean for W properties conservation in operation.

[1] R.A. Pitts et al., J. Nucl. Mater 438, S48 (2013). [2] Y. Ueda et al., Fusion Engineering and Design 89, 7-8, 901-906 (2014).

Plasma-Material Interactions during burning-plasma relevant conditions

R.P. Doerner for the PISCES Research Team

Center for Energy Research, University of California in San Diego, La Jolla CA. USA.

Material surfaces surrounding a burning plasma will be subjected to a combination of extreme

heat flux and bombardment by energetic particles consisting of fuel species, He ash, various

impurities and neutrons. This combination of effects can lead to drastic alterations of the

surfaces and can result in changes to the plasma-material interactions. The PISCES linear

plasma facility [1] strives to simulate these conditions as closely as possible to gain an

understanding of the response of materials to this harsh environment before the burning

plasma state is achieved in confinement devices.

Tungsten is the leading candidate for use as the plasma-facing armor in future burning plasma

devices; however it exhibits a wide variety of surface changes when subjected to the

simulated burning plasma environment. The high-flux plasma impinging on the surface

causes changes to the surface that are not apparent during ion beam or low-flux plasma

irradiation of surfaces. Temperature plays a critical role when determining the response of the

surface to the high-flux plasma bombardment; blistering, nano-bubble formation, cracking

and nano-tendril growth are all possibilities. Some of the resulting surface structures can

produce beneficial effects, while others are detrimental. The accumulation of simulated

neutron damage, achieved by using high energy ion beams, also exhibits a temperature

dependence. The interplay between the different effects and how they likely influence each

other will be discussed. In addition, each of these surface states can affect a critical issue, the

migration of tritium through the material. The issue of fuel retention in tungsten exposed to

burning plasma conditions and its influence on whether a burning plasma is self-sustainable

will be described.

[1] R. P. Doerner, M. J. Baldwin and K. Schmid, Physica Scripta T111(2004)75..

Using grazing-incidence small-angle X-ray scattering to measure helium-

induced modification in metals exposed to low temperature plasma

M. Thompsona, P. Klutha, D. Rileyb and C. Corra a Research School of Physics and Engineering, The Australian National University,

Canberra, Australia. b Institute of Materials Engineering, ANSTO, Lucas Heights, NSW, Australia

Helium-induced nano-scale modification has been widely observed for tungsten exposed to

low-temperature helium plasma, leading to the formation of nano-scale bubbles [1] and fuzz-

like structures [2]. This modification is a major concern for the fusion materials community as

they are likely to alter the thermal and mechanical properties of the material over time. Nano-

bubbles in particular are difficult to study as they are very small (many < 2nm in diameter)

and exist below the sample surface. Transmission electron microscopy (TEM) has been the

most widely used technique in the field, but is destructive, time-consuming and suffers from

sampling limitations.

In recent years we have demonstrated grazing incidence small angle x-ray scattering

(GISAXS) to be a powerful complement to existing TEM studies [3]. GISAXS is a

volumetric technique which can produce a diffraction pattern from millions of nano-bubbles

in a matter of seconds, providing information on nano-bubble shapes, size distributions, and,

in some cases, depth distributions. This has allowed nano-bubble formation to be measured

with a hitherto unprecedented level of precision.

Here, we will discuss our recent work applying GISAXS to study nano-bubble formation in

tungsten and the effects plasma fluence and sample temperature have had on these processes.

The GISAXS technique itself will be explained in detail, including the models required for

pattern fitting.

[1] O. El-Atwani, K. Hattar, J.A. Hinks, G. Greaves, S.S. Harilal and A. Hassanein, J. Nucl.

Mater. 458 216–23 (2015)

[2] Y. Ueda, H.Y. Peng, H.T. Lee, N. Ohno, S. Kajita, N. Yoshida, R. Doerner, G. De

Temmerman, V. Alimov, G. Wright, J. Nucl. Mater. 442 S267–72 (2013)

[3] M. Thompson, R. Sakamoto, E. Bernard, N. Kirby, P. Kluth, D. Riley and C. Corr, J.

Nucl. Mater. 473 6–12 (2016)

Micro- and Nanostructures fabricated by ion-track technology and their

exposure to high-energy sub-ps PW class lasers

M.E. Toimil-Molaresa, A. Spendea,b, L. Movsesyana,b, L. Burra,b, M.F. Wagnera,b , C.

Trautmanna,b, D. Khaghanic, P. Neumayerc a Materials Research Department, GSI Helmholtz Center for Heavy Ion Research, Darmstadt,

Germany. b Materials Science, Technical University Darmstadt, Germany

c Plasma Physics Department, GSI Helmholtz Center for Heavy Ion Research, Darmstadt,

Germany.

In this talk, the fabrication of nanowires and nanotubes in etched ion-track membranes will be

presented. The potential of this technique to fabricate large arrays of micro- and nanowires

rendering excellent control on wire size (diameter and length), morphology, crystalline

structure, and composition will be discussed. Ion-track technology makes use of high-energy

heavy ions (MeV to GeV) to produce ion tracks in foils of insulating material (e.g. polymers,

mica). The tracks can be preferentially dissolved in an appropriate chemical solution, and

subsequently enlarged to pores. Compared to other templates, ion-track membranes offer

well-controlled pore diameter (between ~ 15 nm and few µm), an extremely high length-to-

diameter ratio (>103), as well as the possibility to adjust number density and relative

orientation of the pores via the irradiation conditions. By electrochemical deposition, micro-

and nanowires of different materials such as gold, copper, bismuth compounds, nickel,

platinum, or zinc oxide are synthesized in the channels [1-3]. Composition and

crystallographic characteristics are successfully controlled by the deposition parameters. By

atomic layer deposition, nanotubes of SiO2, TiO2, and Al2O3 with controlled wall thickness

and inner diameter as small as ~ 8 nm have been fabricated [4]. In addition, we will report on

recent results on the exposure of Cu and Au micro-wire arrays freestanding on few

micrometer thin metallic foils to the high-energy sub-ps PW-class laser PHELIX of GSI. In

collaboration with the plasma physics department, hot electron and x-ray generation, as well

as proton acceleration were investigated, showing increased particle yields and larger cut-off

energies [5].

[1] M.E. Toimil-Molares, Beilstein J. Nanotechnol. 3, 860 (2012). [2] L. Movsesyan et al. Sem. Sci. and Tech. 31, 014006 (2015). [3] L. Burr et al. The Journal of Physical Chemistry C 119, 20949 (2015). [4] A. Spende et al. Nanotechnology 26, 335301 (2015). [5] D. Khaghani, M. Lobet, B. Borm, L. Burr, F. Gartner, L. Gremillet, L. Movsesyan, O.

Rosmej, M.E. Toimil-Molares, F. Wagner, and P. Neumayer, submitted (2016)

Modulation of Photoluminescence Emissions in Rare-Ion Doped Laser

Crystals by Ion Implanted Embedded Nanoparticles

Weijie Niea, Ruiyun Hea, Rang Lia, Shengqiang Zhoub and Feng Chena aSchool of Physics, Shandong University, Jinan, China.

bHelmholtz-Zentrum Dresden-Rossendorf, Institute of Ion Beam and Materials Research,

Dresden, Germany.

Metallic nanoparticles (NPs) embedded in rare-earth doped dielectrics are intriguing for a

broad range of scientific and technologic applications such as chemical and biological sensors,

surface-enhanced spectroscopies, photo detection, light harvesting and optical nanodevices

[1]. The absorption and photoluminescence (PL) characteristics of the dielectrics may be

modified by the plasmonic excitation of metallic NPs due to the surface plasmon resonance

(SPR). The absorption of the incident electromagnetic field at the NPs localized regions can

be enhanced significantly compared with the dielectrics without nanoparticles. Nd:YAG is a

very important gain medium for solid-state lasing. In the work, we report on the

photoluminescence modulation of neodymium (Nd3+) ions in Nd:YAG single crystal by

embedded gold NPs, which were fabricated by Au ion implantation with the following

annealing for activation. The absorption enhancement to different extent was observed in the

Nd:YAG crystal due to the variation of the fluence of Au ion implantation. As the excited

state of the Nd3+ ions lies within the SPR band of the gold NPs, the photoluminescence of

Nd3+ ions can be modulated with the effect of either enhancement or quenching in the

Nd:YAG crystal. In our work, the PL intensity of Nd3+ ions for 4F3/2→ 4I9/2 transition at ~890

nm was enhanced or quenched gradually with the increase of SPR absorption of Au NPs from

470 nm to 510 nm, which repeats the SPR band of Au NPs. This work paves a way to

modulate the PL emissions of the laser crystals for diverse applications.

[1] J. A. Jiménez, Phys. Chem. Chem. Phys. 15, 17587 (2013).

[2] L. Sánchez-García et al., Adv. Mater. 26, 6447-6453 (2014).

Mechanism of swift-heavy ion induced nanoparticle elongation above and

below the track formation threshold

K. Nordlunda, , I. Sahlberga, A. A. Leinoa, P. Kluthb, H. Amekurac, and F. Djurabekovaa

a University of Helsinki, Finland

b Research School of Physics and Engineering, The Australian National University, Canberra,

Australia.

c National Institute for Materials Science (NIMS), Tsukuba, Japan

The mechanism of nanoparticle elongation has remained up to debate until recently. We

present here results from large-scale MD simulations of swift heavy ion irradiation into Au

nanoclusters embedded in silica compared to experiments. The simulations show that the

mechanism of elongation is as follows. The swift heavy ion creates an underdense track in the

silica. When the ion happens to pass close to the center of an embedded nanocluster, the

lattice heating also melts the nanocluster. The molten metal then expands into the track, which

is less dense and softer than the silica at the side of the cluster. After a few tens of

picoseconds, the system cools down and the elongated shape is frozen in. Subsequent ions

which again hit at about the center of the elongated cluster can repeat this effect and cause

further elongation [1].

This described mechanism would seem to imply that elongation can happen only above the

track formation threshold, which appears to contradict experiments that indicate shape

changing also below the threshold. To resolve this dilemma, we also ran MD simulations of

ion tracks at stopping power values below the formation of permanent tracks. The results

showed that during the swift heavy ion passage in the material, a transient underdense track

can form, and this can exist long enough to allow for flow of nanocluster atoms into the track

before it closes up. This allows for elongation to occur even below the stopping power

threshold for formation of a permanent track.

[1] A. A. Leino, O. H. Pakarinen, F. Djurabekova, K. Nordlund, P. Kluth, and M. C.

Ridgway, Materials Research Letters 2, 37

(2014).

Lattice location of implanted impurities by emission channeling:

electrical and magnetic dopants in group-III nitrides and ZnO

A. Vantommea, U. Wahlb, J.G. Correiab, and L.M.C. Pereiraa a KU Leuven, Instituut voor Kern- en Stralingsfysica, Leuven, Belgium.

b Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de

Lisboa, Portugal

The properties (electric, optic, and magnetic) of impurities and dopants in semiconductors are

strongly dependent on the lattice sites which they occupy. Although the main occupied site,

for a given impurity-host combination, can often be predicted based on chemical similarities

between impurity and host elements, such expectations fail in many cases. Furthermore,

minority sites (in case of multiple-site occupancy) are even more difficult to predict, detect

and identify. In this talk, we give an overview of recent lattice location studies for impurities

and dopants in group III-nitrides and ZnO, as representative wide-gap semiconductors.

These experiments are based on the emission channeling (EC) technique [1], using radioactive

isotopes produced at the ISOLDE facility at CERN. EC makes use of the charged particles

emitted by a radioactive isotope upon decay. The screened Coulomb potential of atomic rows

and planes determines the anisotropic scattering of the particles emitted isotropically during

the radioactive decay. Along low-index directions of single crystals and epitaxial films, this

anisotropic scattering results in well-defined channeling or blocking effects, which are

detected with a position-sensitive detector. Because these effects strongly depend on the initial

position of the emitted particles, they result in emission patterns which are characteristic of

the lattice site(s) occupied by the probe atoms. In this talk, we present a number of particular

cases that illustrate the strengths of emission channeling when studying systems exhibiting

multiple-site occupancy [2].

[1] H. Hofsäss and G. Lindner, Physics Reports 201, (1991) 121; U. Wahl et al., Nucl.

Instrum. Methods Phys. Res. A 524, (2004) 245.

[2] L.M. Amorim et al., Appl. Phys. Lett. 103 (2013) 262102; L.M.C. Pereira et al., Phys.

Rev. B 84 (2011) 125204.

Quasi in-situ low-temperature ion implantation and RBS defect analysis:

Technical requirements, challenges and applications

E. Wendler

Institut für Festkörperphysik, Friedrich-Schiller-Universität Jena, Jena, Germany.

.

The 400kV Ion Implanter and the 3 MV Tandetron Accelerator of the Institut für

Festkörperphysik in Jena are placed in one accelerator hall which provides the possibility of

introducing two ion beams into one so-called two-beam chamber. This chamber can be

equipped with a goniometer and a Helium refridgerator for sample cooling [1]. The

temperature at the surface of the sample holder can be set to values between 15 K and room

temperature. The goniometer is used for rotating the sample by 35 degrees between the two

beam lines and for orientation of the sample towards the beam of analyzing ions in channeling

condition. A detailed description and some relevant parameters of the two-beam chamber will

be given.

The described setup is used for studying primary ion-beam induced effects in a wide range of

materials. Ion implantation is done in certain ion fluence increments followed by subsequent

ion beam analysis, which is usually Rutherford backscattering spectrometry (RBS) in

channeling mode, without change of temperature or environment of the sample. As the

implanted area and the possibility of sample translation are limited, in most cases all

measurements are done on one and the same spot of the sample. Therefore, the main

challenges in these experiments are possible surface contaminations and the effect of the

analyzing ions on the amount of damage to be measured. Depending on the material under

investigation the analyzing He ions may cause damage annealing or production of additional

damage. It will be shown how one can cope with that and how this may influence the final

results.

The two-beam chamber was applied for investigating radiation effects in various covalent-

ionic materials at temperatures of 15-20 K. These studies reveal some general relations

between susceptibility to ion-beam induced damage formation and binding properties of the

materials. Additionally examples for the application of the two-beam chamber in astro-

physical research will be presented.

[1] B. Breeger, E. Wendler, W. Trippensee, Ch. Schubert, W. Wesch, Nucl. Instrum. Method

Phys. Res. B 174, 661 (2001).

Complementary Methods of Technical Analysis

D.P. Riley

Australian Nuclear Science and Technology Organisation (ANSTO)

Performance within an extreme environment is often dependent on a multitude of factors, each synergistically adding to the accumulative damage of a material or component until failure occurs unpredictably. Confirmation these factors interact, thereby accelerating degradation, often remains speculative as environmental factors (e.g. high temperatures, radiation or contamination) exceed the capabilities of traditional forms of post-failure investigation. Furthermore, confirmation of which factors contribute remains a potentially costly and time consuming process as identification typically only occurs by repeatedly observing discrepancies between predicted and observed performance.

Modern characterisation techniques are rapidly exceeding the capabilities of traditional forms of post-failure investigation, while increasingly aligning with those techniques used to certify materials in operational environments. Complementary analysis techniques capable of assessing the short or long range structure, chemical speciation or relative concentrations of trace isotopes are crucial in evaluating the performance of materials exposed to extreme conditions.

This presentation outlines the Australian domestic capabilities represented by ANSTO’s Nuclear Science & Technology Landmark Infrastructure (NSTLI), which presently include such facilities as the Australian Centre for Neutron Scattering (ACNS), the Australian Synchrotron (AS) and the Centre for Accelerator Science (CAS). Examples of how these facilities have been integrated to solve complex research questions for extreme environments will be included, while mechanisms for engaging with ANSTO to access this infrastructure will also be outlined.

Ion track etched nanopore membranes characterized by small angle x-ray

scattering

A. Hadleya, P. Mota-Santiagoa, H. Hosseina, A.Nadzria, M. Grigga, N. Kirbyb, C.Trautmannc,

M. E. Toimil-Molaresc and P. Klutha a Research School of Physics and Engineering, The Australian National University,

Canberra, Australia. b Australian Synchrotron, Melbourne, Australia.

c GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany.

When a highly energetic heavy ion passes through a target material, the damaged region left

in its wake exhibits preferential etching over the bulk. The etching process creates very high

aspect ratio channels of up to tens of microns in length, with pore openings as small as a few

nanometers. Using this technique, so called “etched ion track membranes” can be fabricated

in a variety of materials including polymers, minerals, and the thin films typically used in

semiconductor processing such as silicon dioxide (SiO2) and silicon nitride (Si3N4).

We are seeking to develop a better understanding of the ion track etching process and its

dependence on the un-etched track structure through a unique combination of complementary

characterisation techniques including synchrotron based small angle x-ray scattering (SAXS),

Monte-Carlo simulation and advanced electron microscopy. Freestanding SiO2 and Si3N4

membranes were irradiated with 185 MeV 179Au ions at the ANU Heavy Ion Accelerator

Facility. Polycarbonate foils, SiO2, and Si3N4 films were irradiated with 1.1 GeV 179Au ions at

the GSI UNILAC in Darmstadt, Germany. Low irradiation fluences in the order of 1x108

ions/cm2 were chosen to avoid significant overlap of the pores during etching.

Pores formed by this method are highly parallel with very low size distributions. The

morphology of the pores can be cylindrical, conical or double conical, depending on the

etching conditions. SAXS, in combination with Monte-Carlo simulation enables an accurate

reconstruction of the size and shape of the pores. SAXS also enables us to perform in-situ

etching experiments at the Australian Synchrotron, allowing us to determine pore etching

kinetics as a function of etchant concentration and temperature. This is an extremely sensitive

technique, which we hope to extend to the study of ion transport through functionalised

membranes in the future.

Understanding the Processing of Three Dimensional Semiconductor Nano-

Devices using TRI3DYN

J. Englanda, and W. Möllerb a Applied Materials UK Ltd, U.K.

b Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany.

In the semiconductor industry, Moore’s Law is increasingly being satisfied by the use of 3D

nano structures; short channel effects of small (<10nm) planar MOS-FETS have been

overcome by the introduction of three dimensional transistors (FinFETs, nano-wires) and the

density of memory cells has been increased by expanding structures into the third dimension

(3D NAND). To process such small structures and consider the use of ion beam techniques in

applications beyond doping, ion implantation equipment requires high productivity at low

energies (<1keV) and often at high ion fluences (>1015 ions/cm2). These requirements

demand new ion based processes using plasma immersion and beamline based ion implanters.

To help understand novel ion beam processes, very successful computer programs (e.g.

SRIM) have been available for some time that model ion beam interactions with substrates

using the binary collision approximation (BCA). However, it is no longer sufficient only to

consider ions implanted into planar Si substrates that remain largely unchanged. Deposition,

sputtering and mixing effects in varied materials must now be followed in three dimensional

structures that alter during a process. This talk will describe use of TRI3DYN [1] to model

examples of deposition, doping and sputtering of leading edge semiconductor devices.

Comparison of TRI3DYN models to experimental results (e.g. TEM, MEIS) guide

interpretation of metrology, reveal surprising effects of familiar mechanisms acting in three

dimensional geometries and often uncover mechanisms beyond those described under the

BCA.

[1] W. Möller, Nucl. Instrum. Meth. Phys. Res. B 322(2014)23

The analysis of nanopores in Ge ion implanted Ge and Si1-xGex alloys

H. S. Alkhaldia,b, F. Kremerc, J. Hansend, A. Nylandsted-Larsend, P. Mota-Santiagoa A.

Nadzria, D. Schauriesa and P. Klutha. aResearch School of Physics and Engineering, The Australian National University, Canberra,

Australia. bDepartment of Physics, College of Education- Jubail, Dammam University, Dammam 1982,

Saudi Arabia. cCentre for Advanced Microscopy, The Australian National University, Canberra ACT 2601.

dDepartment of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark.

It is well known that bombardment of crystalline Ge (c-Ge) leads to the formation of porosity

at moderate ion fluences above about 1015 ions/cm2 at room temperature (RT)[1, 2]. The

porous structure consists of columnar pores and separated by nanometer sized sidewalls. Ion

bombardment of c-Si under comparable implantation conditions, on the other hand, does not

show pore formation. In this study we investigate the formation of porous structures in Ge and

Si1-xGex alloys (x= 0.83, and 0.77) under keV Ge ion irradiation at irradiation temperatures

between room temperature to 200 °C. The evolution of the porous microstructure is highly

dependent on the ion fluence and the irradiation temperature, as well as the substrate

stoichiometry. Porosity is observed in both alloys where the Si content does not exceed 23%.

Transmission electron microscopy (TEM) and Small Angle X-ray Scattering (SAXS) were

used to measure the pore radius and the sidewall thickness. SAXS does not require elaborate

sample preparation and yields superior statistics of the feature size distributions as it probes

much larger sample volumes than TEM, which is restricted to areas of only a few hundred

nanometers. We found that a core shell cylinder model is appropriate to fit the SAXS data and

yields results that agree well with those from TEM. The results suggest no significant increase

in pore size as a function of ion fluence, while the sidewall thickness slightly increases with

increasing Si content.

[1] I. H. Wilson, J.Appl. Phys., vol. 53, p. 1698, 1982. [2] B. Stritzker, R. G. Elliman, and J. Zou, Nucl. Instrum. Methods Phys. Res., Sect. B., vol.

175, pp. 193-196, Apr 2001.

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