A5082901577- Ion-surface interactions and analysis
- Particle physics theoretical and experimental studies
- Graphene research and applications
- Quantum Chromodynamics and Particle Interactions
- Electron and X-Ray Spectroscopy Techniques
- Diamond and Carbon-based Materials Research
- Integrated Circuits and Semiconductor Failure Analysis
- Atomic and Molecular Physics
- High-Energy Particle Collisions Research
- Electronic and Structural Properties of Oxides
- Magnetic confinement fusion research
- Semiconductor materials and devices
- Particle Detector Development and Performance
- Neutrino Physics Research
- Dark Matter and Cosmic Phenomena
- Nanopore and Nanochannel Transport Studies
- Astrophysics and Cosmic Phenomena
- Particle accelerators and beam dynamics
- Nuclear Physics and Applications
- Plasma Diagnostics and Applications
- ZnO doping and properties
- X-ray Spectroscopy and Fluorescence Analysis
- 2D Materials and Applications
- Luminescence Properties of Advanced Materials
- GaN-based semiconductor devices and materials
TU Wien
2016-2025
University of Applied Sciences Technikum Wien
2022
Institut für Technische und Angewandte Physik (Germany)
2021
Helmholtz-Zentrum Dresden-Rossendorf
2010-2020
Technische Universität Dresden
2013-2015
Mansoura University
2012
Johannes Gutenberg University Mainz
1999-2007
European Organization for Nuclear Research
1998
Max Planck Institute for Plasma Physics
1985-1997
Istituto Nazionale di Fisica Nucleare
1990-1992
Abstract The way conduction electrons respond to ultrafast external perturbations in low dimensional materials is at the core of design future devices for (opto)electronics, photodetection and spintronics. Highly charged ions provide a tool probing electronic response solids extremely strong electric fields localized down nanometre-sized areas. With ion transmission times order femtoseconds, we can directly probe local dynamics an ultrathin foil on this timescale. Here report ability...
The impact of a highly charged ion onto solid gives rise to charge exchange between the and target atoms, so that slow gets neutralized in vicinity surface. Using Ar Xe ions surface-only material graphene as target, we show neutralization deexcitation proceeds on sub-10 fs time scale. We further demonstrate multiple Interatomic Coulombic Decay (ICD) model can describe observed ultrafast deexcitation. Other mechanisms involving nonradiative decay quasimolecular orbital formation during are...
Experimental charge exchange and energy loss data for the transmission of slow highly charged Xe ions through ultrathin polymeric carbon membranes are presented. Surprisingly, two distinct exit state distributions accompanied by dependent losses observed. The exhibiting large shows a quadratic dependency on incident indicating that equilibrium stopping force values do not apply in this case. Additional angle resolved measurements point significant contribution elastic loss. observations show...
The roughness of a surface is known to have strong influence on the sputtering process.Commonly used 1D Monte Carlo codes for calculating sputter yields show good agreement with experimental data only comparably flat surfaces, whereas local ion incidence angles, shadowing and redeposition in both magnitude angular dependence rough surfaces.In present work, we therefore investigated tungsten samples largely different roughness, characterised by atomic force confocal microscopy.A highly...
The individual impacts of slow ($300\text{ }\text{ }\mathrm{eV}/\mathrm{amu}$) highly charged Xe ions induce nanometer sized pitlike structures on the KBr (001) surface. volume these shows a strong dependence potential energy. Total sputter yields from atomically flat terraces are determined by imaging single ion impact sites. yield initial charge state combined with structure formation at low and high-fluence irradiations indicates that agglomeration defects into complex centers plays major...
Porous single-layer molybdenum disulfide (MoS2) is a promising material for applications such as DNA sequencing and water desalination. In this work, we introduce irradiation with highly charged ions (HCIs) new technique to fabricate well-defined pores in MoS2. Surprisingly, find linear increase of the pore creation efficiency over broad range potential energies. Comparison atomistic simulations reveals critical role energy deposition from ion through electronic excitation defect process...
SDTrimSP is a popular simulation program to compute several effects of the interaction between an impinging ion and solid, such as implantation ranges, damage formation or sputtering surface atoms. We now introduce graphical user interface for make its operation more accessible broad group users. It written separate Python not restricted any specific operating system. The allows quick easy start well direct evaluation simulations. Its capabilities are demonstrated here in form example cases,...
We describe the use of slow highly charged ions as a simple tool for fabrication nanopores with well-defined diameters typically between 10 and 20 nm in freestanding, 1 thick carbon nanomembranes (CNMs). When CNMs are exposed to flux ions, example Xe40+, each individual ion creates circular nanopore, size which depends on kinetic potential energy impinging ion. The controlled uniform opens path application CNM based filters nanobiotechnology.
The impact of individual slow highly charged ions (HCI) on alkaline earth halide and alkali surfaces creates nano-scale surface modifications. For different materials energies a wide variety topographic alterations have been observed, ranging from regularly shaped pits to nanohillocks. We present experimental evidence for the creation thermodynamically stable defect agglomerations initially hidden after irradiation but becoming visible as upon subsequent etching. A well defined threshold...
We investigated the response of wurzite GaN thin films to energetic ion irradiation. Both swift heavy ions (92 MeV Xe23+, 23 I6+) and highly charged (100 keV Xe40+) were used. After irradiation, samples using atomic force microscopy, grazing incidence small angle x-ray scattering, Rutherford backscattering spectroscopy in channelling orientation time flight elastic recoil detection analysis. Only irradiation induced changes on surface GaN, when appearance nanoholes is accompanied by a...
Graphene electrodes and deep eutectic solvents (DESs) are two emerging material systems that have individually shown highly promising properties in electrochemical applications. To date, however, it has not been tested whether the combination of graphene DESs can yield synergistic effects electrochemistry. We therefore study behavior a defined monolayer centimeter-scale, which was produced by chemical vapor deposition transferred onto insulating SiO2/Si supports, common DES choline...
Slow highly charged ions have been utilized recently for the creation of monotype surface nanostructures (craters, calderas, or hillocks) in different materials. In present study, we report on ability slow xenon (^{129}Xe^{Q+}) to form three types LiF(100) surface. By increasing charge state from Q=15 Q=36, shape impact induced changes craters hillocks crossing an intermediate stage caldera structures. A dimensional analysis reveals increase height up 1.5 nm as a function potential energy...
Abstract Structuring of 2D materials and their heterostructures with ion beams is a challenging task, because typically low energies are needed to avoid damage substrate. In addition, at the very first monolayers material, ions not yet in charge equilibrium, i.e. they may either up or neutralize depending on velocity. The change electronic structure during scattering affects energy, which can be transferred recoil therefore energy available for defect formation. order make reliable use...
Studies of the surface charge dynamics on femtosecond timescale in 2D materials following ion impact yield six times higher electron emission for graphene comparison to MoS${}_{2}$, bridging gap from ultrafast laser physics beams.
Hollow atoms (HAs) are an exotic type of matter formed when a highly charged ion impacts on surface, capturing multiple electrons into excited states, leaving intermediate electronic states empty. Although experimental fingerprints HAs were found in high-resolution x-ray spectra, it has been widely believed that decay too rapidly to be studied directly. Using simulation code for the full deexcitation cascade HAs, based rates from atomic structure codes we show lifetime HA, scattered under...
Multipactor discharges can cause severe problems in high voltage rf systems like antennae or transmission lines of ion cyclotron resonance heating (ICRH) nuclear fusion devices, where they may initiate gas breakdown. To study this eventual transition from a starting multipactor into an ordinary discharge detailed investigations were performed using parallel plate geometry, 50 MHz operating frequency and up to one kilovolt amplitude. Measurements electric data (rf amplitude, absorbed...
Both in Ohmically and beam-heated L-mode discharges of ASDEX, the electron-temperature (Te) profile shape can be varied over a wide range by choice safety factor qa. The power-deposition profile, on contrary, has no effect Te shape. In current-free W-VII-A stellarator plasmas, such invariance property is found. An independent constraint seems to fix current distribution j(r) tokamak, which defines conditions electron heat transport.Received 4 February...
We report the formation of nano-sized pits on poly(methyl methacrylate) after exposure to slow highly charged ion beams. The are formed polymer surface as a direct result individual impacts. Intermittent contact mode atomic-force microscopy was employed study size evolution in dependence potential and kinetic energies incident ions. A energy threshold value approximately 7?keV found for pit formation. Above this an increase results increasing volume, while shape can be tuned by varying energy.
Conditions for ion track formation in single crystal SrTiO3 and TiO2 (rutile) after irradiations using swift heavy beams with specific energies below 1 MeV/amu were investigated this work. Rutherford backscattering spectroscopy channeling was used to measure tracks the bulk, while atomic force microscopy observation of on surfaces. Variations sizes respective thresholds observed under random, near-channeling conditions close normal incidence. These variations are attributed specifics...