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Holger Kersten

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Papers by Holger Kersten

Analysis of passive calorimetric probe measurements at high energy influxes

EPJ Techniques and Instrumentation, Jan 19, 2017

High energy influxes increase the complexity of passive calorimetric probe measurements because o... more High energy influxes increase the complexity of passive calorimetric probe measurements because of an increasing temperature of the surrounding materials like the probe holder. This leads to a distinctively different evolution of the probe temperature compared to low energy influxes. Different established methods for the analysis of passive calorimetric probe data are presented and it is shown that they are not applicable for high energy influx measurements resulting in the requirement of a novel analysis approach. Such an approach is given in this paper by the combination of the exponential and the linear method. The high energy influx measurements are studied for a commercial atmospheric pressure plasma jet, in order to illustrate our suggested modified approach.

Modelling of argon-acetylene dust-forming plasma

HAL (Le Centre pour la Communication Scientifique Directe), Jul 15, 2020

Editorial Microplasmas: scientific challenges & technological opportunities

Diagnostics of Nano-Particle Formation in Process Plasmas

Bulletin of the American Physical Society, Oct 15, 2015

The main sources of particle generation during plasma surface processing and the formation of nan... more The main sources of particle generation during plasma surface processing and the formation of nano-composite materials are (i) the formation of large molecules, mesoscopic clusters and particles in the plasma bulk by chemically reactive gases, and (ii) the formation and incorporation of particles at surfaces (target, substrate) by means of plasma-wall interaction. The plasma process promotes the particle formation by excitation, dissociation and reaction of the involved species in the gas phase. The different stages of the particle growth in the gas phase can be observed by various plasma diagnostics as mass spectrometry, laser induced evaporation, photo-detachment, IR absorption, microwave cavity measurements, Mie scattering and self-excited electron resonance spectroscopy (SEERS). Common diagnostics of particle formation also use the observation and analysis of harmonics and other discharge characteristics. Especially the early stages of the particle growth are not well investigated since they are experimentally inaccessible by standard methods as mentioned above. A novel collection method based on neutral drag was tested in order to get a better insight into the early stages of particle growth. The experiments were performed in an asymmetric, capacitively coupled rf-discharge, where multiple growth cycles can be obtained. Making use of the correlation between the particle growth cycles and the bias voltage as well as the phase angle between discharge current and voltage it was possible to monitor each growth process in-situ. This allowed to collect particles at any desired stage of the growth cycle via the neutral drag method. Size distributions of the nanoparticles at the different stages of the growth cycle were determined ex-situ by transmission electron microscopy. The observed correlations of particle size and bias voltage, which can be used for prediction of the particle growth, are qualitatively explained. Furthermore, the change of the electron density in the plasma during the growth cycles has been monitored by microwave interfereomtery and the nano-particle formation and deposition was observed in-situ by XPS and NEXAFS at a synchrotron beamline. In collaboration with E.

Diagnostics of particle forming process plasmas

Force probes for development and testing of different electric propulsion systems

EPJ Techniques and Instrumentation, Jun 7, 2022

Diagnostics with force probes in plumes of electric propulsion systems for spacecraft (thrusters)... more Diagnostics with force probes in plumes of electric propulsion systems for spacecraft (thrusters) are presented. This contribution focuses on showing example measurements with force probes for the most common gridless ion thruster types. The gridless thrusters are investigated at typical operation modes with a force probe at fixed or variable positions in the plume. The probe measures the force on a tiny plate that is attached to a sensitive cantilever in the plume. The elastic deflection of the cantilever is measured interferometrically and translated into a proportional force. Several variants of the instrument have been developed. A HEMP thruster is investigated with a variant of the force probe that simultaneously measures two components of the force vector. With this vectorial probe, it is possible to determine the force vector acting on the probe target while moving the probe through the thruster plume. A Hall thruster is investigated with a simplified variant of the probe, which measures the force along one axis and is equipped with an additional shutter in front of the target. This allows monitoring over long periods of operation. Finally, a force probe is used as an indirect thrust balance for a FEEP thruster. In this case, the force probe can collect the entire plume.

Effects of process conditions on the chemistry of an Ar/C <sub>2</sub> H <sub>2</sub> dust‐forming plasma

Plasma Processes and Polymers, Apr 2, 2019

A volume-averaged model and numerical simulations are used to clarify the effects of process cond... more A volume-averaged model and numerical simulations are used to clarify the effects of process conditions on the plasma chemistry and species initiating the formation of nanoparticles in an Ar/C2H2 plasma. It is shown that Ar/C2H2 plasmas with low electron density, moderate input flux of acetylene and an electron energy distribution function (EEDF) close to the Druyvesteyn EEDF are the most suitable for the production of carbonaceous nanoparticles. These results are verified by a direct comparison with experimental data and enable to formulate recommendations for future experiments with a controlled growth of nanoparticles in chemically-active plasmas.

Micro-particles as calorimetric probes in a low-pressure rf-discharge

Precise systematic measurements of particle temperatures in a dusty low-pressure plasma have been... more Precise systematic measurements of particle temperatures in a dusty low-pressure plasma have been performed in argon and molecular gas mixtures. At low pressures, the underlying energy balance could be consistently described. Measured particle temperatures and modeled energy fluxes between particles and plasma are presented.

Local extraction of nanoparticles from a dusty CCRF discharge

HAL (Le Centre pour la Communication Scientifique Directe), Mar 4, 2018

Spatiotemporal sampling of growing nanoparticles in an acetylene plasma

Journal of Applied Physics, 2020

The dynamics of carbonaceous nanoparticle (NP) evolution in its cyclic growth process in a capaci... more The dynamics of carbonaceous nanoparticle (NP) evolution in its cyclic growth process in a capacitively coupled RF plasma is studied using multiple diagnostic methods. We designed a simple method using biased substrates for spatiotemporal collection of growing NPs at different positions inside the particle cloud and at different time steps during the growth cycle. In addition, self-bias voltage and laser light scattering are in situ measured to monitor the nanoparticle growth. Subsequently, the collected nanoparticles are characterized by scanning electron microscopy (SEM). Correlations between the self-bias voltage and SEM results are presented. We show that different threshold potentials are needed to overcome the confinement of the NPs for collection. This is explained with the spatial and temporal variation of the plasma potential, the NP size, and the ion drag inside the particle cloud. Moreover, the arrangement of the locally collected NPs on the substrate is found to depend o...

Nanoparticle cloud evolution in an acetylene dusty plasma

The synthesis of nanoparticles for various technological applications requires a perfect control ... more The synthesis of nanoparticles for various technological applications requires a perfect control of their growth kinetics and dynamical behavior in the plasma. One important aspect that has to be taken into account for obtaining nanoparticles with desired size and density, is that nanoparticle growth is a cyclic phenomenon in typical low pressure reactive plasmas. This behavior can be easily observed by measuring plasma or discharge characteristics like the self-bias voltage, the plasma emission or the gas pressure. These successive generations can be also clearly evidenced using laser light scattering (LLS) to directly observe the evolution of the nanoparticle cloud. A laser sheet coupled with a high-resolution CCD camera reveals the details of this cyclic behavior and especially the role of the void in this process. Once the nanoparticles have reached a sufficiently big size, a void (central dust-free region) starts to appear in the middle of the cloud. Its size progressively incr...

Modeling of argon–acetylene dusty plasma

Plasma Physics and Controlled Fusion, Nov 13, 2018

The properties of an Ar/C2H2 dusty plasma (ion, electron and neutral particle densities, effectiv... more The properties of an Ar/C2H2 dusty plasma (ion, electron and neutral particle densities, effective electron temperature and dust charge) in glow and afterglow regimes are studied using a volume-averaged model and the results for the glow plasma are compared with mass spectrometry measurements. It is shown that dust particles affect essentially the properties of glow and afterglow plasmas. Due to collection of electrons and ions by dust particles, the effective electron temperature, the densities of argon ions and metastable atoms are larger in the dusty glow plasma comparing with the dust-free case, while the densities of most hydrocarbon ions and acetylene molecules are smaller. Because of a larger density of metastable argon atoms and, as a result, of the enhancement of electron generation in their collisions with acetylene molecules, the electron density in the afterglow dusty plasma can have a peak in its time-dependence. The results of numerical calculations are in a good qualitative agreement with experimental results.

Particle-in-Cell Simulation of a Down-Scaled HEMP Thruster

Transactions of the Japan Society for Aeronautical and Space Sciences, aerospace technology Japan, 2016

Conventional and non-conventional diagnostics of a stable atmospheric pressure DC normal glow microplasma discharge intended for in situ TEM studies

Plasma Sources Science and Technology, 2022

A simple setup utilizing parallel flat electrodes with a 50–150 μm interelectrode distance divide... more A simple setup utilizing parallel flat electrodes with a 50–150 μm interelectrode distance divided by a Kapton spacer with a 1 mm diameter whole as discharge region intended for in situ transmission electron microscope studies is presented. The rather small setup operated in Ar or He results in an atmospheric pressure DC normal glow discharge and is investigated using various diagnostics. I–V characteristics show a glow-like behavior of the microplasma. Significant differences due to the working gas, electrode material and electrode distance have been observed. Currents in the range of 0.5–3 mA resulted in electrode potentials of 140–190 V for most experimental conditions. Optical emission spectroscopy and imaging revealed stable plasma operation and enabled the determination of current densities (approx. 16 mA mm−2 for He, or 28 mA mm−2 for Ar) independent of the input current as the discharge channel grows in diameter. Sheath thicknesses in the range of a few μm have been calculat...

Correlation between properties of direct current magnetron sputtered thin niobium nitride films and plasma parameters

Thin Solid Films, 2022

Diagnostics of Energy Fluxes in Dusty Plasmas

Die Geschichte der Gasentladungsphysik

Vakuum in Forschung und Praxis, 2018

SummaryThe History of Gas Discharge PhysicsObservation and study of the impressive polar lights m... more SummaryThe History of Gas Discharge PhysicsObservation and study of the impressive polar lights marks the beginning of the gas discharge physics. Even though a remarkable progress was reached by the improvement of gas discharge tubes. The first constructed tube goes back to the Englishman Hauksbee. After that the German glassblower Heinrich Geißler developed more innovative discharge tubes by reducing the gas pressure and by using electrodes of aluminium. The Geißler tubes enabled a lot of scientists such as Plücker, Hittorf and Tesla to study the properties of glow discharges in more detail. At the same time Sir William Crookes developed similar tubes, which found a use in the laboratories of English physicists. Ultimately there were more seminal insights which led to the development of plasma physics as a seperate field and as foundation for many industrial applications.

Correlation between sputter deposition parameters and I-V characteristics in double-barrier memristive devices

Journal of Vacuum Science & Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena, 2019

Sputter deposition is one of the most important techniques for the fabrication of memristive devi... more Sputter deposition is one of the most important techniques for the fabrication of memristive devices. It allows us to adjust the concentration of defects within the fabricated metal-oxide thin film layers. The defect concentration is important for those memristive devices whose resistance changes during device operation due to the drift of ions within the active layer while an electric field is applied. Reversible change of the resistance is an important property for devices used in neuromorphic circuits to emulate synaptic behavior. These novel bioinspired hardware architectures are ascertained in terms of advantageous features such as lower power dissipation and improved cognitive capabilities compared to state-of-the-art digital electronics. Thus, memristive devices are intensively studied with regard to neuromorphic analog systems. Double-barrier memristive devices with the layer sequence Nb/Al/Al2O3/NbOx/Au are promising candidates to emulate analog synaptic behavior in hardwar...

Plasmatechnik 4.0

Vakuum in Forschung und Praxis, 2018

SummaryPlasma Technology 4.0 – State of the art, developments and expectationsNew technologies of... more SummaryPlasma Technology 4.0 – State of the art, developments and expectationsNew technologies offer great opportunities for plasma applications. This fact is also known by the players in surface technology who deal intensively with these current topics. In everyday practice there are already good examples of integrable IoT services for process technology right through to networked business processes. The expectations are high and the concerns as well. Beginning with social aspects of the man‐machine interface through standardization to cyber security there are numerous topics that are discussed in the community. The potential of the plasma technology drives the stakeholders and inspires to more and more new research projects for intelligent process diagnostics and process control.

Modification of a metal nanoparticle beam by a hollow electrode discharge

Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, 2016

Treatment of nanoparticles (NPs) in complex environments, such as plasmas, is of interest for the... more Treatment of nanoparticles (NPs) in complex environments, such as plasmas, is of interest for the fabrication of advanced nanomaterials with desired properties and also from a physical point of view. Here, the authors investigate the mutual interaction between silver NPs and a radio frequency (RF) plasma at different conditions by combining a cylindrical hollow electrode with a gas aggregation source. The investigation of the NP deposits and the morphology of the casted films shows that the applied RF discharge significantly changes the path of the NPs as well as the NP size distribution in the beam. Starting from a neutral NP beam, it is observed that most of the NPs leave the plasma region with negative charge(s), yet the fraction of positively charged NPs grows with power. Furthermore, the plasma characteristics are slightly influenced by the NP flux since the passing NPs collect the plasma charge carriers.

Analysis of passive calorimetric probe measurements at high energy influxes

EPJ Techniques and Instrumentation, Jan 19, 2017

High energy influxes increase the complexity of passive calorimetric probe measurements because o... more High energy influxes increase the complexity of passive calorimetric probe measurements because of an increasing temperature of the surrounding materials like the probe holder. This leads to a distinctively different evolution of the probe temperature compared to low energy influxes. Different established methods for the analysis of passive calorimetric probe data are presented and it is shown that they are not applicable for high energy influx measurements resulting in the requirement of a novel analysis approach. Such an approach is given in this paper by the combination of the exponential and the linear method. The high energy influx measurements are studied for a commercial atmospheric pressure plasma jet, in order to illustrate our suggested modified approach.

Modelling of argon-acetylene dust-forming plasma

HAL (Le Centre pour la Communication Scientifique Directe), Jul 15, 2020

Editorial Microplasmas: scientific challenges & technological opportunities

Diagnostics of Nano-Particle Formation in Process Plasmas

Bulletin of the American Physical Society, Oct 15, 2015

The main sources of particle generation during plasma surface processing and the formation of nan... more The main sources of particle generation during plasma surface processing and the formation of nano-composite materials are (i) the formation of large molecules, mesoscopic clusters and particles in the plasma bulk by chemically reactive gases, and (ii) the formation and incorporation of particles at surfaces (target, substrate) by means of plasma-wall interaction. The plasma process promotes the particle formation by excitation, dissociation and reaction of the involved species in the gas phase. The different stages of the particle growth in the gas phase can be observed by various plasma diagnostics as mass spectrometry, laser induced evaporation, photo-detachment, IR absorption, microwave cavity measurements, Mie scattering and self-excited electron resonance spectroscopy (SEERS). Common diagnostics of particle formation also use the observation and analysis of harmonics and other discharge characteristics. Especially the early stages of the particle growth are not well investigated since they are experimentally inaccessible by standard methods as mentioned above. A novel collection method based on neutral drag was tested in order to get a better insight into the early stages of particle growth. The experiments were performed in an asymmetric, capacitively coupled rf-discharge, where multiple growth cycles can be obtained. Making use of the correlation between the particle growth cycles and the bias voltage as well as the phase angle between discharge current and voltage it was possible to monitor each growth process in-situ. This allowed to collect particles at any desired stage of the growth cycle via the neutral drag method. Size distributions of the nanoparticles at the different stages of the growth cycle were determined ex-situ by transmission electron microscopy. The observed correlations of particle size and bias voltage, which can be used for prediction of the particle growth, are qualitatively explained. Furthermore, the change of the electron density in the plasma during the growth cycles has been monitored by microwave interfereomtery and the nano-particle formation and deposition was observed in-situ by XPS and NEXAFS at a synchrotron beamline. In collaboration with E.

Diagnostics of particle forming process plasmas

Force probes for development and testing of different electric propulsion systems

EPJ Techniques and Instrumentation, Jun 7, 2022

Diagnostics with force probes in plumes of electric propulsion systems for spacecraft (thrusters)... more Diagnostics with force probes in plumes of electric propulsion systems for spacecraft (thrusters) are presented. This contribution focuses on showing example measurements with force probes for the most common gridless ion thruster types. The gridless thrusters are investigated at typical operation modes with a force probe at fixed or variable positions in the plume. The probe measures the force on a tiny plate that is attached to a sensitive cantilever in the plume. The elastic deflection of the cantilever is measured interferometrically and translated into a proportional force. Several variants of the instrument have been developed. A HEMP thruster is investigated with a variant of the force probe that simultaneously measures two components of the force vector. With this vectorial probe, it is possible to determine the force vector acting on the probe target while moving the probe through the thruster plume. A Hall thruster is investigated with a simplified variant of the probe, which measures the force along one axis and is equipped with an additional shutter in front of the target. This allows monitoring over long periods of operation. Finally, a force probe is used as an indirect thrust balance for a FEEP thruster. In this case, the force probe can collect the entire plume.

Effects of process conditions on the chemistry of an Ar/C <sub>2</sub> H <sub>2</sub> dust‐forming plasma

Plasma Processes and Polymers, Apr 2, 2019

A volume-averaged model and numerical simulations are used to clarify the effects of process cond... more A volume-averaged model and numerical simulations are used to clarify the effects of process conditions on the plasma chemistry and species initiating the formation of nanoparticles in an Ar/C2H2 plasma. It is shown that Ar/C2H2 plasmas with low electron density, moderate input flux of acetylene and an electron energy distribution function (EEDF) close to the Druyvesteyn EEDF are the most suitable for the production of carbonaceous nanoparticles. These results are verified by a direct comparison with experimental data and enable to formulate recommendations for future experiments with a controlled growth of nanoparticles in chemically-active plasmas.

Micro-particles as calorimetric probes in a low-pressure rf-discharge

Precise systematic measurements of particle temperatures in a dusty low-pressure plasma have been... more Precise systematic measurements of particle temperatures in a dusty low-pressure plasma have been performed in argon and molecular gas mixtures. At low pressures, the underlying energy balance could be consistently described. Measured particle temperatures and modeled energy fluxes between particles and plasma are presented.

Local extraction of nanoparticles from a dusty CCRF discharge

HAL (Le Centre pour la Communication Scientifique Directe), Mar 4, 2018

Spatiotemporal sampling of growing nanoparticles in an acetylene plasma

Journal of Applied Physics, 2020

The dynamics of carbonaceous nanoparticle (NP) evolution in its cyclic growth process in a capaci... more The dynamics of carbonaceous nanoparticle (NP) evolution in its cyclic growth process in a capacitively coupled RF plasma is studied using multiple diagnostic methods. We designed a simple method using biased substrates for spatiotemporal collection of growing NPs at different positions inside the particle cloud and at different time steps during the growth cycle. In addition, self-bias voltage and laser light scattering are in situ measured to monitor the nanoparticle growth. Subsequently, the collected nanoparticles are characterized by scanning electron microscopy (SEM). Correlations between the self-bias voltage and SEM results are presented. We show that different threshold potentials are needed to overcome the confinement of the NPs for collection. This is explained with the spatial and temporal variation of the plasma potential, the NP size, and the ion drag inside the particle cloud. Moreover, the arrangement of the locally collected NPs on the substrate is found to depend o...

Nanoparticle cloud evolution in an acetylene dusty plasma

The synthesis of nanoparticles for various technological applications requires a perfect control ... more The synthesis of nanoparticles for various technological applications requires a perfect control of their growth kinetics and dynamical behavior in the plasma. One important aspect that has to be taken into account for obtaining nanoparticles with desired size and density, is that nanoparticle growth is a cyclic phenomenon in typical low pressure reactive plasmas. This behavior can be easily observed by measuring plasma or discharge characteristics like the self-bias voltage, the plasma emission or the gas pressure. These successive generations can be also clearly evidenced using laser light scattering (LLS) to directly observe the evolution of the nanoparticle cloud. A laser sheet coupled with a high-resolution CCD camera reveals the details of this cyclic behavior and especially the role of the void in this process. Once the nanoparticles have reached a sufficiently big size, a void (central dust-free region) starts to appear in the middle of the cloud. Its size progressively incr...

Modeling of argon–acetylene dusty plasma

Plasma Physics and Controlled Fusion, Nov 13, 2018

The properties of an Ar/C2H2 dusty plasma (ion, electron and neutral particle densities, effectiv... more The properties of an Ar/C2H2 dusty plasma (ion, electron and neutral particle densities, effective electron temperature and dust charge) in glow and afterglow regimes are studied using a volume-averaged model and the results for the glow plasma are compared with mass spectrometry measurements. It is shown that dust particles affect essentially the properties of glow and afterglow plasmas. Due to collection of electrons and ions by dust particles, the effective electron temperature, the densities of argon ions and metastable atoms are larger in the dusty glow plasma comparing with the dust-free case, while the densities of most hydrocarbon ions and acetylene molecules are smaller. Because of a larger density of metastable argon atoms and, as a result, of the enhancement of electron generation in their collisions with acetylene molecules, the electron density in the afterglow dusty plasma can have a peak in its time-dependence. The results of numerical calculations are in a good qualitative agreement with experimental results.

Particle-in-Cell Simulation of a Down-Scaled HEMP Thruster

Transactions of the Japan Society for Aeronautical and Space Sciences, aerospace technology Japan, 2016

Conventional and non-conventional diagnostics of a stable atmospheric pressure DC normal glow microplasma discharge intended for in situ TEM studies

Plasma Sources Science and Technology, 2022

A simple setup utilizing parallel flat electrodes with a 50–150 μm interelectrode distance divide... more A simple setup utilizing parallel flat electrodes with a 50–150 μm interelectrode distance divided by a Kapton spacer with a 1 mm diameter whole as discharge region intended for in situ transmission electron microscope studies is presented. The rather small setup operated in Ar or He results in an atmospheric pressure DC normal glow discharge and is investigated using various diagnostics. I–V characteristics show a glow-like behavior of the microplasma. Significant differences due to the working gas, electrode material and electrode distance have been observed. Currents in the range of 0.5–3 mA resulted in electrode potentials of 140–190 V for most experimental conditions. Optical emission spectroscopy and imaging revealed stable plasma operation and enabled the determination of current densities (approx. 16 mA mm−2 for He, or 28 mA mm−2 for Ar) independent of the input current as the discharge channel grows in diameter. Sheath thicknesses in the range of a few μm have been calculat...

Correlation between properties of direct current magnetron sputtered thin niobium nitride films and plasma parameters

Thin Solid Films, 2022

Diagnostics of Energy Fluxes in Dusty Plasmas

Die Geschichte der Gasentladungsphysik

Vakuum in Forschung und Praxis, 2018

SummaryThe History of Gas Discharge PhysicsObservation and study of the impressive polar lights m... more SummaryThe History of Gas Discharge PhysicsObservation and study of the impressive polar lights marks the beginning of the gas discharge physics. Even though a remarkable progress was reached by the improvement of gas discharge tubes. The first constructed tube goes back to the Englishman Hauksbee. After that the German glassblower Heinrich Geißler developed more innovative discharge tubes by reducing the gas pressure and by using electrodes of aluminium. The Geißler tubes enabled a lot of scientists such as Plücker, Hittorf and Tesla to study the properties of glow discharges in more detail. At the same time Sir William Crookes developed similar tubes, which found a use in the laboratories of English physicists. Ultimately there were more seminal insights which led to the development of plasma physics as a seperate field and as foundation for many industrial applications.

Correlation between sputter deposition parameters and I-V characteristics in double-barrier memristive devices

Journal of Vacuum Science & Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena, 2019

Sputter deposition is one of the most important techniques for the fabrication of memristive devi... more Sputter deposition is one of the most important techniques for the fabrication of memristive devices. It allows us to adjust the concentration of defects within the fabricated metal-oxide thin film layers. The defect concentration is important for those memristive devices whose resistance changes during device operation due to the drift of ions within the active layer while an electric field is applied. Reversible change of the resistance is an important property for devices used in neuromorphic circuits to emulate synaptic behavior. These novel bioinspired hardware architectures are ascertained in terms of advantageous features such as lower power dissipation and improved cognitive capabilities compared to state-of-the-art digital electronics. Thus, memristive devices are intensively studied with regard to neuromorphic analog systems. Double-barrier memristive devices with the layer sequence Nb/Al/Al2O3/NbOx/Au are promising candidates to emulate analog synaptic behavior in hardwar...

Plasmatechnik 4.0

Vakuum in Forschung und Praxis, 2018

SummaryPlasma Technology 4.0 – State of the art, developments and expectationsNew technologies of... more SummaryPlasma Technology 4.0 – State of the art, developments and expectationsNew technologies offer great opportunities for plasma applications. This fact is also known by the players in surface technology who deal intensively with these current topics. In everyday practice there are already good examples of integrable IoT services for process technology right through to networked business processes. The expectations are high and the concerns as well. Beginning with social aspects of the man‐machine interface through standardization to cyber security there are numerous topics that are discussed in the community. The potential of the plasma technology drives the stakeholders and inspires to more and more new research projects for intelligent process diagnostics and process control.

Modification of a metal nanoparticle beam by a hollow electrode discharge

Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, 2016

Treatment of nanoparticles (NPs) in complex environments, such as plasmas, is of interest for the... more Treatment of nanoparticles (NPs) in complex environments, such as plasmas, is of interest for the fabrication of advanced nanomaterials with desired properties and also from a physical point of view. Here, the authors investigate the mutual interaction between silver NPs and a radio frequency (RF) plasma at different conditions by combining a cylindrical hollow electrode with a gas aggregation source. The investigation of the NP deposits and the morphology of the casted films shows that the applied RF discharge significantly changes the path of the NPs as well as the NP size distribution in the beam. Starting from a neutral NP beam, it is observed that most of the NPs leave the plasma region with negative charge(s), yet the fraction of positively charged NPs grows with power. Furthermore, the plasma characteristics are slightly influenced by the NP flux since the passing NPs collect the plasma charge carriers.