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A model for the simulation of ion beam extraction from an electron-cyclotron resonance ion source is proposed. It is based on the simple fact that charged particles follow magnetic field lines. Therefore, magnetic field lines are used to generate initial conditions for ray-tracing. This model reproduces in simulation experimentally obtained results. The importance of correlations in phase-space caused by the magnetic field is shown in the simulation. This model also describes the physics of space-charge and its compensation in the extracted (fast) ion beam by low-energy electrons. Simulation provides the possibility to test theoretical assumptions, as well as to optimize technical designs.

Space-charge effects are familiar to students of solid state physics, semiconductor devices, and surface science. They are usually estimated under the strong depletion or space-charge layer approximation (SCLA), whose limitations are rarely fully discussed. A formal description of these effects is presented, followed by numerical solutions to a one-dimensional Poisson's equation. This equation is valid in cases of charge depletion and of mild accumulation near surfaces and interfaces. Poisson's equation as it applies to a film/substrate interface is analyzed to obtain the boundary condition for the potential at the metallurgical junction. A practical applied example discusses the impact of depletion effects on the determination of the charge carrier concentration by Hall effect measurement in homoepitaxial semiconductor thin films. Examples are highlighted where the SCLA is not an accurate approximation. [ABSTRACT FROM AUTHOR]

X-ray free-electron lasers (XFELs) and megaelectronvolt ultrafast electron diffractometers (MeV UEDs) are revolutionary scientific instruments that allow visualizing the dynamics of elementary excitations in a wide range of systems from atoms and molecules to phonons, magnons and plasmons. Femtosecond (fs) electron beams are at the heart of XFELs and MeV UEDs, and the formation of fs electron beams with ultrahigh brightness is the subject of active research. We report an interesting regime of non-adiabatic temporal compression of electron beams by two orders of magnitude. Via analytical calculations and numerical simulations, we show that few MeV electron bunches can be trapped and compressed by a strong electromagnetic field within a half of the field wavelength. Furthermore, in a multi-cell accelerating cavity, the bunch is first compressed and then accelerated, thus allowing one to preserve very short bunch duration. For example, a 3 ps 16 pC 1 MeV electron bunch is compressed to 21 fs rms and accelerated to 12 MeV in a TESLA superconducting cavity. Another example is the production of 1.2 fs 16 fC 3.3 MeV bunches with a coherence length of 20 nm and and an energy spread less than 3 keV. The discovered mechanism of compression, which is another mode of velocity bunching, opens the door for obtaining very high electron brightness.

We investigate by molecular dynamics simulations (Torfason et al., 2015; 2016) a beam of electrons released via field emission from a planar cathode surface of 1 μm2 with an inhomogeneous two-level work function, φlow and φhigh. A rectangular grid, where each cell can have one out of two values of the work function, is used as a model. The number of cells in the grid ranges from 6 × 6 to 96 × 96. We compare a periodic checkerboard arrangement with disordered distributions of patches. We perform multiple simulations and randomize the pattern each time. We study the beam behavior by calculating the position and velocity of each electron, r.m.s. emittance, and the brightness of the electron beam. The emittance increases while brightness decreases, with the mean distance between patches with φlow when they are in minority, and they switch the behavior versus the mean distance between patches with φhigh when these patches are in minority, respectively. The Coulomb interaction between all particles is fully included in our simulations. [ABSTRACT FROM AUTHOR]

Molecular dynamics simulations, with full Coulomb interaction and self-consistent field emission, are used to examine mutual space–charge interactions between beams originating from several emitter areas, in a planar infinite diode. The simulations allow observation of the trajectory of each individual electron through the diode gap. Results show that when the center-to-center spacing between emitters is greater than half of the gap spacing the emitters are essentially independent. For smaller spacing the mutual space–charge effect increases rapidly and should not be discounted. A simple qualitative explanation for this effect is given. [ABSTRACT FROM AUTHOR]

This study investigates grain growth in the perovskite oxide strontium titanate in an electric field. The seeded polycrystal technique was chosen as it provides a sensitive and controlled setup to evaluate the impact of different parameters on grain growth due to the well‐defined driving force for grain growth. Current blocking electrodes were used to prevent Joule heating. The results show faster grain growth, and thus, higher grain‐boundary mobility at the negative electrode. It is argued that the electric field causes point‐defect redistribution, resulting in a higher oxygen vacancy concentration at the negative electrode. The local oxygen vacancy concentration is suggested to affect the space‐charge potential at the grain boundaries. A thermodynamic treatment of the grain‐boundary potential at a grain boundary without field shows that for a high oxygen vacancy concentration less space‐charge and less accumulation of cationic defects to the boundary occurs. Therefore, at the negative electrode, a higher oxygen vacancy concentration results in less space‐charge and less accumulation of cationic defects. The lower degree of defect accumulation requires less diffusion of segregated defects during grain‐boundary migration, so that at the negative electrode faster grain growth is expected, as found in the experiments. [ABSTRACT FROM AUTHOR]

High proton conductivity and good chemical stability are keys to development of new electrolytes for PC-SOFCs as the next-future energy generation systems. However, the extensive use of new polycrystalline materials as solid electrolytes is still avoided, since the grain boundary response usually leads to a decrease in total conductivity due to electrical blocking effect. Here, we present our results on the space-charge modeling of impedance spectroscopy data obtained for Ba 3 Ca 1.18 Nb 1.82- x R x O 9-δ proton conducting ceramics, where x  = 0, 0.30 and R = Y 3+ , Gd 3+ , Sm 3+ , Nd 3+ are doping agents. Non-stoichiometric barium calcium niobate perovskites have received much attention as potential solid electrolytes for proton conducting solid oxide fuel cells. We show that despite their increased grain conductivity, the doped ceramics possess Schottky barriers that are higher than those observed for undoped Ba 3 Ca 1.18 Nb 1.82 O 9-δ . In view of the space-charge model, proton depletion at the space-charge layer is the reason for the reduction of grain boundary conductivity in the doped compositions. Our findings are important for the understanding of proton conduction mechanisms in polycrystalline materials, which may allow future optimization of new doped electrolytes based on barium calcium niobate perovskites. [ABSTRACT FROM AUTHOR]

Y-doped BaZrO 3 (BZY) can be deposited epitaxially on MgO (0 0 1) and the considered interface serves as a model system for studying heterointerface properties of protonic conductors. In this study, the defect chemistry of the interface between ZrO 2 -terminated BaZrO 3 (0 0 1) and MgO (0 0 1) was investigated by first-principles calculations and space-charge theory. Segregation energies from the BZY bulk to the interface ZrO 2 and MgO layers were calculated for effectively charged protons, oxygen vacancies, Y-acceptors as well as cation vacancies. Protons were found to exhibit a strong tendency for segregating to the interface, particularly to an oxide ion in the MgO layer, rendering a net positive charge of the interface. According to the applied thermodynamic space-charge models, the interface potential could reach more than 1 V under the Mott-Schottky approximation, with depletion regions extending up to 2 nm into BZY. With fully equilibrated Y-segregation profiles, the interface potential was significantly diminished to about 0.2 V at 573 K and 0.025 bar H 2 O. While the interface was found to be close to saturated by protons under most condition, it was concluded that proton conduction along the interface could not contribute significantly to the in-plane conductivity of BZY films deposited on MgO substrate. [ABSTRACT FROM AUTHOR]

Photoinduced space-charges in organic optoelectronic devices, which are usually caused by poor mobility and charge injection imbalance, always limit the device performance. Here we demonstrate that photoinduced space-charge layers, accumulated at organic semiconductor-insulator interfaces, can also play a role for photocurrent generation. Photocurrent transients from organic devices, with insulator-semiconductor interfaces, were systematically studied by using the double-layer model with an equivalent circuit. Results indicated that the electric fields in photoinduced space-charge layers can be utilized for charge generation and can even induce a photovoltage reversal. Such an operational process of light harvesting would be promising for photoelectric conversion in organic devices.

Ferromagnetic metals show great prospects in ultralow-power-consumption spintronic devices, due to their high Curie temperature and robust magnetization. However, there is still a lack of reliable solutions for giant and reversible voltage control of magnetism in ferromagnetic metal films. Here, a novel space-charge approach is proposed which allows for achieving a modulation of 30.3 emu/g under 1.3 V in Co/TiO 2 multilayer granular films. The robust endurance with more than 5000 cycles is demonstrated. Similar phenomena exist in Ni/TiO 2 and Fe/TiO 2 multilayer granular films, which shows its universality. The magnetic change of 107% in Ni/TiO 2 underlines its potential in a voltage-driven ON-OFF magnetism. Such giant and reversible voltage control of magnetism can be ascribed to space-charge effect at the ferromagnetic metals/TiO 2 interfaces, in which spin-polarized electrons are injected into the ferromagnetic metal layer with the adsorption of lithium-ions on the TiO 2 surface. These results open the door for a promising method to modulate the magnetization in ferromagnetic metals, paving the way toward the development of ionic-magnetic-electric coupled applications., (© 2022 Wiley-VCH GmbH.)

This study demonstrates the hydrothermal treatment of core-shell polytetrafluoroethylene (PTFE) nanoparticles decorated with TiO 2 (h -PTFE@TiO 2); this material exhibits strain-induced local dipole enhancement of the space-charge piezopotential that improves the photocatalytic effect. Under acoustic cavitation, dielectric barrier discharge and electric dipole formation are initiated in voids within the PTFE nanoparticles and at the TiO 2 –PTFE interface. The h -PTFE@TiO 2 nanoparticles (NPs) have exceptionally high catalytic activity in organic dye degradation because of the local dipole enhancement of photoinduced charge separation with a carrier lifetime of 3.14 ns. The observed rate constant of the h- PTFE@TiO 2 NPs in the piezophototronic reaction reaches 0.1388 min−1, which is 17 times that of the photocatalytic reaction (0.0084 min−1) and 66 times that of the piezocatalytic reaction (0.0021 min−1). Computational simulation reveals that large strain-induced space charge piezoelectric polarization induces an internal electric field between the unsaturated PTFE (fluorine vacancies) and TiO 2 surface. The piezopotential has a critical role in band bending at PTFE-TiO 2 interfaces to enhance the electron-hole separation when PTFE is constrained in TiO 2 shells. Results of piezoresponse force microscopy reveal that the piezoelectric coefficient d 33 of PTFE is approximately 79.77 pCN−1. The findings provide insights into catalytic activity for environmental remediation. This study demonstrates the hydrothermal treatment of core-shell polytetrafluoroethylene (PTFE) nanoparticles decorated with TiO2; this material exhibits strain-induced local dipole enhancement of the space-charge piezopotential improves the photocatalytic effect. Computational simulation reveals that large strain-induced space charge piezoelectric polarization induces an internal electric field between the unsaturated PTFE (fluorine vacancies) and TiO2 surface. Considerable local dipole enhancement was observed in the fluorine vacancies of the PTFE, further enhancing the space-charge piezophototronic effect that benefits the performance of the material when used as a photocatalyst. [Display omitted] • Space charge piezoelectric polarization occurs between the fluorine vacancies of PTFE and TiO 2 surface. • The piezoelectric coefficient d 33 of PTFE is approximately 79.77 pCN−1. • A local dipole enhancement of PTFE@TiO 2 photoinduced charge separation with a carrier lifetime of 3.14ns. • Piezopotential modulates the band bending at PTFE-TiO 2 interfaces to enhance electron-hole separation. [ABSTRACT FROM AUTHOR]

We present theoretical and numerical studies of matching sub-femtosecond space-charge-dominated electron bunch into the Laser-plasma Wake Field Accelerator (LWFA) foreseen at the SINBAD facility. The longitudinal space-charge (SC) effect induced growths of the energy spread and longitudinal phase-space chirp are major issues in the matching section, which will result in bunch elongation, emittance growth and spot size dilution. In addition, the transverse SC effect would lead to a mismatch of the beam optics if it were not compensated for. Start-to-end simulations and preliminary optimizations were carried out in order to understand the achievable beam parameters at the entrance of the plasma accelerator. [ABSTRACT FROM AUTHOR]

Hydroxyapatite (HA) is a major component of bone in humans and animals. Until about 10 years ago, it was considered to have a centrosymmetric crystal structure and could not contribute to the well-known piezoelectric effect in bone. This review describes the theoretical and experimental studies that showed that HA does have a non-centrosymmetric structure. Recent experiments have shown that HA exhibits piezoelectricity, pyroelectricity, and ferroelectricity. It has been made in the form of thick films and as space-charge electrets. It has an important biomedical application as an implant for bone cell attachment and growth. [ABSTRACT FROM AUTHOR]

Acceptor-doped cerium oxides are a promising solid electrolyte material for solid oxide fuel cells (SOFCs) due to their exceptionally high oxygen ion conductivity. Typical solid electrolytes are polycrystalline with a number of grain boundaries, and it is common for grain boundaries to block the motion of mobile oxygen ions as they migrate from one grain to the next. Accordingly, it is important precisely to measure the grain boundary conductivities of doped cerium oxides, particularly at the temperature of relevance (>500 °C). Here, we undertake a quantitative analysis of the transport properties of singly and doubly doped cerium oxides. So that we may precisely extract the grain boundary contribution out of the total conductivity at an elevated temperature (>500 °C), both epitaxial and polycrystalline thin films of the oxides are grown via pulsed layer deposition (PLD) on two different insulating, single-crystal substrates: Al 2 O 3 (0001) and SiO 2 (001), and these are then characterized by a range of analysis tools, in this case TEM, SEM, XRD, ICP-MS and AFM. These samples with controlled microstructures, in combination with in-plane ionic conductivity measurements by impedance spectroscopy as a function of the thickness, temperature and p O 2 , enable us precisely to measure the grain boundary conductivity of the doped ceria at temperatures ranging from 620 to 700 °C. The impact of the number and type of dopants on the transport properties are also explored. [ABSTRACT FROM AUTHOR]

Time-dependence of space-charge built-up at the ITO/organic semiconductor interface has been investigated for the first time using the charge extraction by linearly increasing voltage (CELIV) technique in the dark. It will be demonstrated that space-charge next to an ITO/P3HT interface is extracted during the initial CELIV ramp establishing a non-equilibrium situation whose temporal recovery can be probed by utilizing sequentially prolonged delay times for successive voltage ramps. It will be reported that the build-up time constant for space charge at the ITO/P3HT interface amounts to 230 μs. The dynamics of the relatively slow charge transfer at the interface of the transparent conducting oxide and the organic semiconductor as well as time-limiting processes will be discussed by considering tunneling, thermal detrapping and diffusion of the involved electrons and holes. It will be shown that thermal detrapping of electrons from molecules with their ground state close the center of the HOMO-DOS to vibronic states within the same molecule followed by tunneling to neighboring molecules with their not occupied ground state within the tail states of the DOS is the time limiting process and responsible for the long build-up time. [ABSTRACT FROM AUTHOR]

Current gain degradation in irradiated bipolar junction transistors is primarily due to excess base current caused by enhanced carrier recombination in the emitter-base space-charge region (SCR). Radiation-induced traps at the interface between silicon and the bipolar base oxide facilitate the recombination process primarily above the sensitive emitter-base junction. This leads to an increase in surface recombination current in the SCR, which is a non-ideal component of the BJT’s base current characteristic under active bias conditions. In this paper, we derive a precise analytical model for surface recombination current that captures bias dependencies typically omitted from traditional models. This improved model is validated by comparisons to these traditional approaches. [ABSTRACT FROM AUTHOR]

The influence of space-charge on ion cyclotron resonances and magnetron eigenfrequency in a gas-filled Penning ion trap has been investigated. Off-line measurements with K + 39 using the cooling trap of the WITCH retardation spectrometer-based setup at ISOLDE/CERN were performed. Experimental ion cyclotron resonances were compared with ab initio Coulomb simulations and found to be in agreement. As an important systematic effect of the WITCH experiment, the magnetron eigenfrequency of the ion cloud was studied under increasing space-charge conditions. Finally, the helium buffer gas pressure in the Penning trap was determined by comparing experimental cooling rates with simulations. [ABSTRACT FROM AUTHOR]

Abstract: The present LANSCE injector utilizes two 750-keV Cockcroft–Walton (CW) based injectors for simultaneous injection of H+ and H− beams into 800-MeV accelerator. To reduce long-term operational risks, the new project to replace the existing H+ CW injector with a Radio-Frequency Quadrupole (RFQ) accelerator is underway [1]. The new injector requires a Low-Energy Beam Transport (LEBT). An ion source and 2-solenoid magnetic LEBT have been designed and optimized to transport beams over a wide range of space-charge neutralization and transverse emittance, while allowing sufficient space for diagnostics and a beam deflector. The design layout minimizes the beam size in the LEBT and potential emittance growth due to solenoid aberrations and nonlinear space-charge forces. This paper describes the details of the LEBT design activity. [Copyright &y& Elsevier]

Abstract: This work is devoted to the study of the interaction between pulses of electromagnetic radiation and space-charge waves in laser-plasmas settings. We analyse modes depending only on the co-moving coordinate of the beam frame, but make no a priori assumption on the longitudinal-to-transverse aspect ratio of the pulses. The model thus constructed allows us to investigate regimes where transverse and longitudinal length scales of the pulses are comparable. Resonant and nonresonant excitations of space-charge modes are analyzed and the endurance of trains of solitons against transverse effects is clarified. [Copyright &y& Elsevier]

Abstract: The foremost challenge for Heavy-Ion Fusion (HIF) is achieving sufficiently low emittances and small energy spreads in the presence of intense space-charge, to achieve the high deposition densities necessary for pellet ignition. The University of Maryland Electron Ring (UMER) uses intense low-energy electron beams to access the scaled physics of HIF drivers. In particular, the long path-length propagation in UMER presents an opportunity to study, at realistic scales, the longitudinal beam dynamics and manipulations required for such a driver. With the use of induction modules, as in the ion machines such as NDCX-II, the resulting bunch dynamics show evidence of space-charge waves excited by an initial mismatch between the detailed initial beam distribution at the bunch ends and the applied focusing waveforms, persisting with multiple damped reflections propagating along the bunch flat-top. Using the induction module we are able to suppress space-charge waves with great accuracy, at amplitudes that include wave steepening prior to the formation of solitary wave trains. The longitudinal dynamics largely dominates when no containment fields are applied, coupling through the natural chromaticity of the ring even within the first turn. After subsequent turns, the bunch elongates and wraps the circumference of the machine multiple times; eventually reaching a point of instability that has also been shown through simulation, obtaining excellent agreement when the detailed longitudinal dynamics of the experiment are carefully incorporated into the model. [Copyright &y& Elsevier]

Abstract: NDCX-II, the second neutralized drift compression experiment, is a moderate energy, high current accelerator designed to drive targets for warm dense matter and IFE-relevant energy coupling studies, and to serve as a testbed for high current accelerator physics. As part of the design process, studies were carried out to assess the sensitivities of the accelerator to errors, and to further optimize the design in concert with the evolving pulsed power engineering. The Warp code was used to carry out detailed simulations in both axisymmetric and full 3-D geometry. Ensembles of simulations were carried out to characterize the effects of errors, such as timing jitter and noise on the accelerator waveforms, noise on the source waveform, and solenoid and source offsets. In some cases, the ensemble studies resulted in better designs, revealing operating points with improved performance and showing possible means for further improvement. These studies also revealed a new non-paraxial effect of the final focus solenoid on the beam, which must be taken into account in designing an optimal final focusing system. [Copyright &y& Elsevier]

Laser-driven Plasma Accelerators (LPA) have successfully generated high energy, high charge electron bunches which can reach many kA peak current, over short distances. Space charge issues, even in transport lines as simple as a drift section, have to be carefully taken into account since they can degrade the beam quality, preventing any further application of such electron beams. We analyse the space charge effects within an electron bunch with numerical simulations in order to assess their effect on the beam. We use LPA beam parameters published in previous experimental studies. These studies can give an indication of the working point where space charge can dominate the beam dynamics and has to be taken into account in the application of such beams. [ABSTRACT FROM AUTHOR]

Abstract: At the radioactive ion-beam facility REX-ISOLDE more than 60 different types of radionuclide ions have been post-accelerated to energies up to 3.15MeV/u within the last years. The transmission efficiency of the system has continually increased with gained operation experience. Apart from striving for the highest possible intensity, the beam purity is also of crucial importance for many experiments. For this reason isobaric contaminant suppression in the low energy stage of REX-ISOLDE has been investigated. Until now the Penning trap system REXTRAP was used solely as a device for bunching the incoming quasi-continuous radioactive ion-beam from ISOLDE and reducing the emittance for efficient injection into the REXEBIS charge breeder. The possibility of operating REXTRAP in a mass-resolving mode and injecting bunched beams from the recently installed radiofrequency quadrupole cooler and buncher ISCOOL has been studied in detail. Results related to transmission efficiency,achieved mass-resolving power, and limitations due to space-charge effects are presented. [ABSTRACT FROM AUTHOR]

Abstract: Pulse radiolysis, a stroboscopic method involving the use of an ultrashort electron bunch and ultrashort light, is essential for the observation of ultrafast reactions. The time resolution of pulse radiolysis depends on the electron bunch length. At Osaka University, a 98-fs electron bunch was generated using a photocathode RF gun linac for the development of femtosecond pulse radiolysis. In order to improve the time resolution of pulse radiolysis, the feasibility of sub-femtosecond electron bunch generation using a photocathode RF gun linac and a magnetic bunch compressor was studied in a simulation. Increase in bunch length due to higher-order effects and bunch charge was investigated using the simulation codes PARMELA and ELEGANT. [Copyright &y& Elsevier]

The generation of space charges in polymeric dielectric materials is known to be affected by such inclusions as cross-linking by-products, antioxidants, and moisture. We reported previously that negative heterocharges in XLPE are generated in the presence of acetophenone and sulfur-containing antioxidants. In this paper we describe further experiments using samples containing DCP and three different antioxidants in order to examine the mechanism of this phenomenon. Negative heterocharges near the positive electrode were detected in samples containing both DCP and antioxidants when those samples were soaked in acetophenone. Negative heterocharges were not detected in samples containing either DCP or the antioxidant, even when the sample was soaked in acetophenone. These results demonstrate that a heterocharge is generated by the combined effect of acetophenone and the substance produced by interaction between DCP and the antioxidant. Based on the results of experiments measuring the amount of heterocharge in samples that had been heatpressed at different temperatures, the mechanism of negative heterocharge generation in polymeric dielectric material is inferred. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 172(2): 1–9, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20941 [ABSTRACT FROM AUTHOR]

Abstract: We discuss the scalable parallel solution of the Poisson equation within a Particle-In-Cell (PIC) code for the simulation of electron beams in particle accelerators of irregular shape. The problem is discretized by Finite Differences. Depending on the treatment of the Dirichlet boundary the resulting system of equations is symmetric or ‘mildly’ nonsymmetric positive definite. In all cases, the system is solved by the preconditioned conjugate gradient algorithm with smoothed aggregation (SA) based algebraic multigrid (AMG) preconditioning. We investigate variants of the implementation of SA-AMG that lead to considerable improvements in the execution times. We demonstrate good scalability of the solver on distributed memory parallel processor with up to 2048 processors. We also compare our iterative solver with an FFT-based solver that is more commonly used for applications in beam dynamics. [Copyright &y& Elsevier]

A modest dc electric field markedly reduced the tensile flow stress at high temperatures in three polycrystalline oxides, i.e. MgO, Al2O3 and yttria-stabilized tetragonal ZrO2 (Y-TZP). The reduction in flow stress ΔσE in Y-TZP consisted of three components: (i) ΔσT due to Joule heating, (ii) [image omitted] a rapid, reversible component obtained in on-off and electric field step tests and (iii) [image omitted] the cumulative effect of the field on microstructure. Only ΔσT and [image omitted] occurred in MgO and Al2O3. It is concluded that [image omitted] results from a reduction in the electrochemical potential for the formation of vacancies corresponding to the diffusion of the rate-controlling ion in the space-charge at the grain boundary. The calculated magnitude of the space-charge zone width and its temperature and solute composition dependence are in accord with theory and experiment; [image omitted] is attributed mainly to the retardation of grain growth by the field. The retardation could be due to one or more of the following effects of the field on the space-charge zone: (i) an increase in the segregated solute ions, (ii) a decrease in grain boundary energy and (iii) a decrease in solute ion mobility. [ABSTRACT FROM AUTHOR]

Abstract: The applicability of extremely thin non-electroneutral membranes for ion-selective electrodes (ISEs) is investigated. A theoretical treatment of potential and concentration profiles in space-charge membranes of ≪1μm thickness is presented. The theory is based on the Nernst–Planck equation for ion fluxes, which reduces to Boltzmann’s formula at equilibrium, and on the Poisson relationship between space-charge density and electric field gradient. A general solution in integral form is obtained for the potential function and the corresponding ion profiles at equilibrium. A series of explicit sub-solutions is derived for particular cases. Membrane systems with up to three different ion species are discussed, including trapped ionic sites and co-extracted ions. Solid-contacted thin membranes (without formation of aqueous films at the inner interface) are shown to exhibit a sub-Nernstian response. The theoretical results are confirmed by numerical simulations using a simplified finite-difference procedure based on the Nernst–Planck–Poisson model, which are shown to be in excellent agreement. [Copyright &y& Elsevier]

Abstract: A self-consistent calculation of the barrier height and of the effective recombination velocity at the interface between a metallic precipitate and a semiconductor matrix has been performed within the Read–Hall–Schockley framework. The recombination has been investigated for Si, Ge and GaAs. The precipitate size has a dramatic effect on recombination due to the enhancement of the surface charge density on the metallic precipitate when the size decreases. The electron beam induced current (EBIC) contrast of metallic precipitate has been investigated. [Copyright &y& Elsevier]