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The hot carrier cooling dynamics in the C-excitonic state of monolayer MoS2 is slowed down by the hot phonon bottleneck and Auger heating effects, as exploited by ultrafast transient absorption spectroscopy. The hot carrier cooling process, determined by the hot phonon bottleneck, can be prolonged through rising the excitation photon energy or increasing the absorbed photon flux. By inducing the Auger heating effect under higher absorbed photon flux, the hot carrier lifetime also increases at the low excitation photon energy. When these two effects are combined under higher excitation photon energy and higher absorbed photon flux, the hot phonon bottleneck is gradually weakened because of Auger recombination. In addition, the similar hot carrier phenomenon can be observed in A/B excitonic states owing to the same physical mechanism. Our work establishes a solid photophysics foundation for 2D transition-metal dichalcogenide applications in advanced energy conversion, optical quantum communication, quantum technology, etc.

The effect of strike angle on the conveying performance of drilling tools was studied using the discrete element method for efficient, reliable and economical auger mining. The results show that there are significant differences in volume fill level and power among the rows of drilling rods and drilling heads at any strike angles. It is necessary to take steps in the retreat process to improve the recovery ratio of the drilling tool. In addition, the increasing positive strike angle and increasing negative strike angle have opposite effects on the overall conveying performance of a drilling tool. To provide the drilling tool with consistent conveying performance, the screw twist direction and rotation direction of the middle drilling rod and middle drilling head should be designed according to the sign of the strike angle. This research has important guiding significance and practical value for the structural design and optimization of drilling tools.

The exponential component of the electron spectrum during Ne–Ne collisions is shown to be associated with the electron transitions from the autoionization term to the continuum. The characteristics of this term have been determined. The exponential shape of the spectrum is explained by the absence of interference between the transition amplitudes as the particles come close together and fly apart due to a high transition probability. For Auger transitions in the quasi-molecule we have determined the dependence of the mean Auger transition energy on the reached internuclear distance, which agrees well with the results of energy level calculations for the Ne–Ne system, and the dependence of the weighted mean Auger transition probability on the observed electron energy Ee. We show that the transition probability decreases significantly with increasing Ee as the internuclear distance decreases, apparently, due to a decrease in the overlap integrals of the wave functions for the interacting electrons. Our analysis allows a coherent picture of ionization in collisions of intermediate-mass ions with keV energies to be formed.

Attosecond pump-attosecond probe spectroscopy is becoming possible due the development of sub-femtosecond free electron laser (FEL) pulses as well as intense high-order harmonic generation-based attosecond sources. Here we investigate theoretically whether these developments can provide access to direct time-resolved measurement of Auger decay through detection of the total yield of an ionic decay product, in analogy to the photodissociation product detection in femtochemistry. We show that the ion yield based measurement is generally possible and in the case of the inner-valence hole decay can be background-free. Extensive first principles calculations are used to optimise the probe photon energies for a variety of prototypical systems.

As an intrigued layered 2D semiconductor material, indium selenide (In2Se3) has attracted widespread attention due to its excellent properties. So far, the carrier dynamics of α-In2Se3 and β-In2Se3 are still lacking a comprehensive understanding, which is essential to enhancing the performance of In2Se3-based optoelectronic devices. In this study, we explored the ultrafast carrier dynamics in thin α-In2Se3 and β-In2Se3via transient absorption microscopy. For α-In2Se3 with a narrower bandgap, band filling and bandgap renormalization jointly governed the time evolution of the differential reflectivity signal, whose magnitude and sign at different delays were determined by the weights between the band filling and bandgap renormalization, depending on the carrier density. For β-In2Se3, whose bandgap is close to the probe photon energy, only positive differential reflectivity was detected, which was attributed to strong band filling effect. In both materials, the lifetime decreased and the relative amplitude of the Auger process increased, when the pump fluence was increased. These findings could provide further insights into the optical and optoelectronic properties of In2Se3-based devices.

Core ionization of DNA begins a cascade of events which could lead to cellular inactivation or death. The created core-hole following an impulse inner-shell ionization of molecules naturally decays in the auger timescale. We simulated charge migration (CM) phenomena following an impulsive core ionization of individual DNA bases at the oxygen K-edge which occurs before Auger decay of the oxygen. Our approach is based on real-time time dependent density functional theory (RT-TDDFT). It is shown that the pronounced hole fluctuation observed around bonds of the initial core-hole results in various valence orbital migrations. Also, the same photo-core-ionized dynamics is studied for the related base pairs. We investigate the role of base pairing and H-bonding interactions in the attosecond CM dynamics. In particular, the creation of a core-hole in the oxygen involved in H-bonding leads to an enhancement of charge migration relative to the respective single bases. Importantly, the hole oscillation of the adenine-thymine base pair upon creation of a core-hole at the oxygen, which does not contribute to the donor-acceptor interactions (not H-bonded), decreases compared to the single thymine base. Understanding the detailed dynamics of the localized core-hole initiating CM process would open the way for chemically controlling DNA damage/repair in the future.

A thermally impossible positive free energy reaction can proceed by electron-orbital-selective excitation. When the Si 2p core level is photo-excited in Pt/SiOx bilayer films, Coulomb repulsion at the final two-hole state localized in the valence band by an interatomic Auger transition induces dissociation of the O atom and formation of a Si–Pt bond. Consequently, Pt2Si silicide is formed by a positive free energy reaction. Under a single particle excitation of the valence band, low probability of the coexistence of the two-hole state for picosecond order suppresses to allow the reaction to proceed.

The paper provides an overview of the research of the working processes of the screw working bodies of technological machines. It is shown that at present such an issue in the theory of auger working bodies as the number of auger turns is necessary, what position of the auger spiral should be in relation to the center, etc. is not completely solved, the solution of these issues can provide increased productivity. In modern conditions, caused by global climatic changes in the world, the requirements for the conditions for the protection of forest zones have increased, which makes it necessary to increase funds for fighting fire in forests and increase the raw material and financial base of specialized forest protection services, which is due to the constant search for new and improvement of old methods of forest fire elimination. Special ground-throwing machines have the greatest efficiency, but they do not have working equipment for pushing combustible materials in the form of a ground cover, dead wood, and felling residues. For these purposes, in our opinion, the most suitable auger working bodies installed in front of the rotor-throwers. Modeling of the working process of screw working bodies is based on the particle dynamics method. In the process of modeling, the forest litter is made in the form of a set (about 5000) spherical elements in diameter, which interact with each other and with the working surfaces of the auger working bodies. The working surfaces of the screw drum are represented from the lateral surface of the cylinder, modeled as a separate geometric figure, and 200 triangles forming a helical surface. It was found that the optimal cutting depth is 8-10 cm, at which the auger almost completely cleans the working strip from the soil layer, but at the same time is not too deeply buried to cause large power losses. The identified main parameters of the auger working bodies will be used to create an effective forest fire ground-throwing machine.

Purpose The purpose of this paper is to address the concern of some stainless steel users. To understand the effect of surface white spots on corrosion performance of stainless steel. Design/methodology/approach White spots appeared on some component surfaces made of 316 L stainless steel in some industrial applications. To address the concern about the pitting performance in the spot areas, the pitting corrosion potential and corrosion resistance were measured in the spot and non-spot areas by means of potentiodynamic polarization and electrochemical impedance spectroscopy and the two different surface characteristics were analytically compared by using optical microscopy, laser confocal microscopy, scanning electron microscopy, x-ray diffraction, energy dispersive spectroscopy and auger energy spectroscopy. The results indicated that the pitting performance of the 316 L stainless steel was not negatively influenced by the spots and the white spots simply resulted from the slightly different surface morphology in the spot areas. Findings The white spots are actually the slightly rougher surface areas with some carbon-containing species. They do not reduce the pitting resistance. Interestingly, the white spot areas even have slightly improved general corrosion resistance. Research limitations/implications Not all surface contamination or roughening can adversely affect the corrosion resistance of stainless steel. Practical implications Stainless steel components with such surface white spots are still qualified products in terms of corrosion performance. Originality/value The surface spot of stainless steel was systematically investigated for the first time for its effect on corrosion resistance and the conclusion was new to the common knowledge.

Auger-type energy exchange plays key roles in the carrier dynamics in nanomaterials due to strong carrier-carrier interactions. However, theoretical descriptions are limited to perturbative calculations of scattering rates on static structures. We develop an accurate and efficient ab initio technique to model Auger scattering with nonadiabatic molecular dynamics. We incorporate the many-body Coulomb matrix into several surface hopping methods and describe simultaneously charge-charge and charge-phonon scattering in the time-domain and in a nonperturbative, configuration-dependent manner. The approach is illustrated with a CdSe quantum dot. Auger scattering between electrons and holes breaks the phonon bottleneck to electron relaxation. The bottleneck is recovered when electrons and holes are decoupled. The simulations correctly reproduce all experimental processes and time scales, including Auger- and phonon-assisted cooling of hot electrons, intraband carrier relaxation, and carrier recombination. Providing detailed insights into the energy flow, the developed method allows studies of carrier dynamics in nanomaterials with strong carrier-carrier interactions.

It is well known that carrier distribution in InGaN multiple quantum wells (MQWs) can be significantly inhomogeneous. However, the conventional ABC recombination model assumes that carriers are uniformly distributed throughout the MQW. In this paper, a modified ABC model that considers the unequal carrier density in the QWs was developed. From the analysis of the developed ABC model, the effective recombination coefficients and modified internal quantum efficiency (IQE) were obtained for an arbitrary carrier distribution in MQWs. The efficiency droop was found to be aggravated as the carrier distribution was increasingly inhomogeneous. However, it was also found that the effect of inhomogeneous carrier distribution alone was not sufficient to explain the IQE droop with the theoretical Auger recombination coefficient based on indirect Auger processes. The developed ABC model is expected to provide insight into the influence of inhomogeneous carrier distributions in MQWs on the efficiency droop in GaN-based light-emitting diodes.

Understanding the scattering process of field injection hot carriers is important for modulating their behaviors, which is the key for improving the efficiency of charge transfer and energy conversion in hot carrier devices. In this work, a significant electron thermalization induced by Auger scattering between a field injection hot hole and a native cold electron has been observed in a vertical single layer graphene/hexagonal boron nitride/few layer graphene (Gr/hBN/FLG) device by measuring the vacuum electron emission characteristics. For the first time, it is found that vacuum electron emission can be measured under both directions of bias within the device. Furthermore, electrons can be emitted even when the applied bias energy is smaller than the work function of the Gr cathode. Further analysis of the emission electron kinetic energy indicates that the low turn-on bias results from the emission of energetic electrons that are ∼3 eV higher than the Fermi level. A semiquantitative model based on hot hole-induced Auger electron emission is established to reproduce the results. All of these findings not only expand our understanding of the hot carrier scattering process in graphene but also provide insights into the applications of hot carrier devices.

Extrusion of feed ensures a high quality of the fi nished product.(Research purpose) To increase structural elements durability of the press extruder by optimizing their strength characteristics.(Materials and methods) The authors studied the technological principle of extrusion. The experiment planning method was applied. They examined the process of press extruder operation with a variable pitch screw during the lentils processing. The strength characteristics of the press-extruder elements were checked during design or strength calculations.(Results and discussion) The authors showed the role of the main geometrical parameters of the extruder screw – the slope of the turn and the cutting step – in the preparation of high-quality grain feed. It was found that the turn pitch should be calculated depending on the friction coeffi cient of the starting material against the press-extruder body, the type and properties of the supplied material. The auger fatigue stresses were determined as a result of constant sign shear load and temperature eff ects. The drive power, the extruder productivity were calculated to clarify the screw characteristics, as well as the hydraulic resistance of the matrix output head, the distance of the technological zones. It was confi rmed that the prefabricated screw structure, consisting of sections with diff erent pitch, gave the press extruder versatility.(Conclusions) The authors found that the key was one of the most loaded structural elements of the press-extruder screw. The maximum calculated voltage from a constant load was calculated – 26.98 megapascals. It was determined that the stress in the cross-section of the key under temperature action was 591 megapascals, which exceeded the yield stress for the selected material, equal to 360 megapascals for steel 45. In the course of experimental studies, a value of impact strength was obtained that corresponded to the standard value of the initially selected steel grade (38 kilojoules per cubic meter), but didn’t meet the requirements for this structural element (at least 50 kilojoules per cubic meter).

Different additive manufacturing (AM) technologies can help produce parts from various materials, but in order to achieve consistent and predictable properties and ensure high quality of 3D-printed objects, these materials shall possess specific properties. In this research, we studied initial properties of a cobalt-chrome-molybdenum–based superalloy powder by using sophisticated techniques such as the scanning electron microscopy (SEM) with an energy-dispersive X-ray spectrometer (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES) and particle-induced X-ray emission (PIXE). The summarised results have shown dispersion of main components (Co, Cr, Mo), an attenuating of Co0.64Cr0.32Mo0.04 with Co0.9Mo0.1 phase, and differences in size, shape, surface roughness, structure and content of S, C, Mn and Si among individual particles. Depending on the particle surface structure, differences in the oxidation of particles have been found. According to Auger survey spectra, the smallest particles had a low concentration of Co and Cr oxides, while the smooth ones had higher contents of metal oxides. These findings could be used to predict behaviour of particles during the additive manufacturing process.

This study focuses on chemical recycling of plastics from waste electrical and electronic equipment (WEEE), which constitutes a problematic waste fraction due to the presence of brominated flame retardants. An auger reactor has been designed and used for this study. Real WEEE material provided by Stena Technoworld has been pyrolyzed under different temperature conditions. The performance of the reactor as well as other important parameters such as the fate of the bromine have been investigated and evaluated. The main outcome of this investigation is to simulate a continuous process, which can be useful for designing a full-scale industrial process. The mass balance results after performing thermal treatment at 400, 500, and 600 °C, showed a high gas yield (44 %wt) at the temperature of 600 °C, which energy content is enough to self-sustain the auger reactor. At the low temperature of 400 °C the oil production reaches its maximum yield as well as maximum concentration of bromine, corresponding to 0.5 wt% in the oil. Several valuable organic compounds have been detected in the oil composition, which can be used as precursors for feedstock recycling producing new plastics.

Using the methods of tunneling, infrared, X-ray photoelectron, Auger, and Raman spectroscopies, X-ray diffraction, and transmission electron microscopy, we study the structure and conductive properties of carbon films synthesized on various metal substrates (Al, Mo, Re, Ta, Ag, Cu, and Pt). The effect of the substrate material on the properties of the carbon film is studied. Based on non-empirical quantum-mechanical calculations, an analysis of the experimental vibrational spectra is carried out. The work function of the substrate material is concluded to depend on the length of the chain fragment.

This study represents the detailed calculation of damage by Auger electrons of radionuclides 99 m T c , 111 I n , 125 I and 123 I to DNA molecules at cellular scales, using Geant4-DNA toolkit. The average number of breaks in DNA are shown as a function of distance from the center of the DNA axis to position of Auger electron decay and compared with results obtained for different models of DNA used by others. The highest damage occurs for electrons with energies below 1 keV, and in proximity of DNA molecule. The calculation of DSB yield per Gy per Dalton is carried out for above radionuclides. The most considerable damage occurs when the distance between an Auger electron-emitting atom and DNA is about 2.5 nm, and 50% decreases happen when the distance is about 3.5 to 4 nm. DSB yield are comparable with other experimental and simulation data, and show a good agreement between our results and other works.

Transition metal dichalcogenide (TMD) semiconductor heterostructures are actively explored as a new platform for quantum optoelectronic systems. Most state of the art devices make use of insulating hexagonal boron nitride (hBN) that acts as a wide-bandgap dielectric encapsulating layer that also provides an atomically smooth and clean interface that is paramount for proper device operation. We report the observation of large, through-hBN photocurrents that are generated upon optical excitation of hBN encapsulated MoSe2 and WSe2 monolayer devices. We attribute these effects to Auger recombination in the TMDs, in combination with an asymmetric band offset between the TMD and the hBN. We present experimental investigation of these effects and compare our observations with detailed, ab-initio modeling. Our observations have important implications for the design of optoelectronic devices based on encapsulated TMD devices. In systems where precise charge-state control is desired, the out-of-plane current path presents both a challenge and an opportunity for optical doping control. Since the current directly depends on Auger recombination, it can act as a local, direct probe of both the efficiency of the Auger process as well as its dependence on the local density of states in integrated devices.

The Auger recombination in bulk semiconductors can quickly depopulate the charge carriers in a nonradiative way, which, fortunately, only has a detrimental impact on optoelectronic device performance under the condition of high carrier density because the restriction arising from concurrent momentum and energy conservation limits the Auger rate. Here, we surprisingly observed enhanced Auger recombination in an α-Fe2O3 single crystal, a wide bandgap semiconductor with low carrier mobility. The Auger process was ascribed to the Coulombically coupled self-trapped excitons (STEs), and the relaxation of momentum conservation due to the strong spatial localization of these STEs should account for the enhancement. The STE-density dependent kinetics suggested that the strong polaronic effect could cause a micro-heterogeneous distribution of STEs in a high-quality bulk single crystal, which also gave rise to the micro-heterogeneous annihilation dynamics, and a stochastic recombination model was developed and successfully described the STE annihilation dynamics.

This publication addresses the impact of selected design parameters of milling auger cutting drums on the loading process, and above all the winding angle of the auger blade. The loading process is often referred to as an auxiliary process because the milling process is considered to be the dominant throughout the work of the cutting drum. The correct determination of the relationship between the mining process and the loading process allows to understand how the individual design and kinematic parameters of the mining drums and the mining machine on which they are installed affect each other. The publication discusses the problem of loading with milling cutting drums and ways to increase its efficiency. The research results of the loading process have been presented, affecting the efficiency of this process in the aspect of various angles of inclination of the auger blades. Based on the tests, conclusions have been formulated that allow for the possible selection of an appropriate winding angle for the auger blade, depending on the granulation of spoil.

In the present work, extensive air showers (EAS) effects are described by estimating the longitudinal development model of EAS at very high energies of various cosmic ray particles. The longitudinal development was simulated for charged particles such as gamma, charged pions and charged muons at very high energies 1017, 1018 and 1019eV. The simulation was performed using an air shower simulator system (AIRES) version 19.04.0. The effect of primary particles, energies, thinning energy and zenith angle (θ) on the number of charged particles (longitudinal development) produced in the EAS was taken into account. The rapprochement of the estimated longitudinal development of the charged particles such as the charged muons and charged pions with the experimental measurements (AUGER experiment) that gave a good agreement for primary proton at the fixed primary energy 1019eV for θ =0˚.

Charge transfer between dissimilar atoms is an essential step for many chemical processes such as corrosion and heterogeneous catalysis, but directly probing the charge transfer has been a challenge. Using the oxygen-copper system as an example, we show that synchrotron-based ambient pressure X-ray photoelectron spectroscopy can be employed to monitor the charge transfer between adsorbates and metal surfaces. It is shown that oxygen chemisorption on Cu surfaces results in an Auger process that differs from the photoexcitation-induced Coster-Kroning transition and can be used to derive the degree of charge transfer in combination with ab initio calculations. The identified chemisorption-induced Auger process may have broader implications for its use as a fingerprint to monitor bond formation and charge transfer between dissimilar atoms.

Drilling and installation of deep foundations typically alter and affect surrounding soils and subsequently affect the adjacent structures. Possible effects on the adjacent structures due to the installation of driven piles have been thoroughly investigated in the literature. However, little attention has been given to other pile installation techniques such as continuous flight auger (CFA). In this paper, unfavorable CFA drilling conditions are discussed and investigated using three-dimensional (3D) finite element analyses. The induced settlements around the piles are calculated to assess the possible adverse effects on surrounding structures. The numerical models are validated using laboratory physical modeling of unfavorable soil drilling conditions reported in the literature. The analyses showed that unfavorable drilling conditions might have a major effect on adjacent structures up to two times the pile length. Parametric numerical modeling has also been conducted to study the influence of different parameters such as soil shear strength parameters, pile length, pile diameter, and soil permeability on the deformation adjacent to CFA pile during construction. The results revealed that soil relative density and permeability have a significant influence on the calculated surface settlement. Finally, several pile group drilling scenarios were investigated to gain insight into the optimum scenario for pile drilling. The analyses show that alternating between drilling piles near the structure and those far from it, may significantly reduce the surface settlement during pile construction.

Purpose: In this work, we set out to provide an experimental setup, using Cs-131, with associated dosimetry for studying relative biological effectiveness (RBE) of Auger emitters.Material and methods: Cs-131 decays by 100% electron capture producing K- (9%) and L- (80%) Auger electrons with mean energies of 26 keV and 3.5 keV, respectively, plus ≈9.4 very low energy electrons (+/K+-ATPase. By this uptake mechanism and the alkali chemistry of Cs+, we argue for its intracellular homogeneous distribution. Cs-131 was added to the cell culture medium of HeLa and V79 Cells. The bio-kinetics of Cs-131 (uptake, release, intracellular distribution) was examined by measuring its intracellular activity concentration over time. Taking advantage of the 100% confluent cellular monolayer, we developed a new and robust dosimetry that is entrusted to a quantity called SC-value.Results: The SC-values evaluated in the cell nucleus are almost independent of the nuclear size and geometry. We obtained dose-rate controlled RBE-values for intracellular Cs-131 decay. Using the γH2AX assay, the RBE was 1 for HeLa cells. Using the clonogenic cell survival, it was 3.9 for HeLa cells and 3.2 for V79 cells.Conclusion: This experimental setup and dosimetry provides reliable RBE-values for Auger emitters in various cell lines.

Cellular dosimetry plays a crucial role in radiobiology and evaluation of the relative merits of radiopharmaceuticals used for targeted radionuclide therapy. The present study aims to investigate the effects of various cell geometries on dosimetric characteristics of several Auger emitters distributed in different subcellular compartments using Monte Carlo simulation. The Geant4-DNA extension of the Geant4 Monte Carlo simulation toolkit was employed to calculate the mean absorbed dose per unit cumulated activity (S value) for different subcellular distributions of several Auger electron-emitting theranostic radionuclides including 99mTc, 111In, 123I, 125I, and 201Tl. The simulations were carried out in various single-cell models of liquid water including spherical, ellipsoidal, spherical spindle, and ellipsoidal spindle cell models. The latter two models which are generalized from the first two models were inspired by the morphologies of spindle-shaped (fusiform) cells, and were developed to provide more realistic modeling of this common geometry observed in many healthy and cancerous cells. Evaluation of the S values calculated for the examined cell models reveals that the differences are small (less than 9%) for the cell ← cell, cell ← cell surface, and nucleus ← nucleus source–target combinations. However, moderate discrepancies are seen (up to 28%) when the nucleus is considered as the target, as well as the radioactivity is either internalized into the cytoplasm or bound to the cell membrane. The findings of the present work suggest that the assumption of spherical cell geometry may provide reasonably accurate estimates of the cellular/nuclear dose for the considered Auger emitters, even for spindle-shaped cells. Of course, this approximation should be used with caution for the nucleus ← cytoplasm and nucleus ← cell surface configurations, since the S-value sensitivity to the cell geometry is somewhat significant in these cases.

Lead halide perovskite nanocrystals (NCs) hold strong promise for a variety of light-harvesting, emitting, and detecting applications, all of which, however, could be complicated by multicarrier Auger recombination. Therefore, complete documentation of the size- and composition-dependent Auger recombination rates of these NCs is highly desirable, as it can guide system design in many applications. Herein we report the synthesis and Auger measurements of monodisperse APbX3 (A=Cs and FA; X=Cl, Br, and I) NCs in an extensive size range (ca. 3-9 nm). The biexciton Auger lifetime of all the NCs scales linearly with the NC volume. The scaling coefficient is virtually independent of the cation but rather depends sensitively on the anion, and is 0.035, 0.085, and 0.142 ps nm-3 for Cl, Br, and I, respectively. In all of these nanocrystals the Auger recombination is much faster than in standard CdSe and PbSe NCs (ca. 1 ps nm-3 ).

In a radiative Auger process, an excited electron relaxes by concomitant emission of a redshifted photon and energy transfer to another electron. Measuring radiative Auger processes in a quantum dot with single-photon resolution enables determination of the energy of single-electron levels as well as their lifetimes.In a multi-electron atom, an excited electron can decay by emitting a photon. Typically, the leftover electrons are in their ground state. In a radiative Auger process, the leftover electrons are in an excited state and a redshifted photon is created(1-4). In a semiconductor quantum dot, radiative Auger is predicted for charged excitons(5). Here we report the observation of radiative Auger on trions in single quantum dots. For a trion, a photon is created on electron-hole recombination, leaving behind a single electron. The radiative Auger process promotes this additional (Auger) electron to a higher shell of the quantum dot. We show that the radiative Auger effect is a powerful probe of this single electron: the energy separations between the resonance fluorescence and the radiative Auger emission directly measure the single-particle splittings of the electronic states in the quantum dot with high precision. In semiconductors, these single-particle splittings are otherwise hard to access by optical means as particles are excited typically in pairs, as excitons. After the radiative Auger emission, the Auger carrier relaxes back to the lowest shell. Going beyond the original theoretical proposals, we show how applying quantum optics techniques to the radiative Auger photons gives access to the single-electron dynamics, notably relaxation and tunnelling. This is also hard to access by optical means: even for quasi-resonantp-shell excitation, electron relaxation takes place in the presence of a hole, complicating the relaxation dynamics. The radiative Auger effect can be exploited in other semiconductor nanostructures and quantum emitters in the solid state to determine the energy levels and the dynamics of a single carrier.

Auger recombination in semiconductors is a many-body phenomenon in which recombination of electrons and holes is accompanied by excitation of other charge carriers. Being nonradiative, it is detrimental to light emission. The excess energy of the excited carriers is normally rapidly converted to heat, making Auger processes difficult to probe directly. Here, we employ a technique in which the Auger-excited carriers are detected by their ability to tunnel out of the semiconductor through a thin barrier, generating a current. We employ vertical van der Waals (vdW) heterostructures with monolayer WSe2 as the semiconductor and the wide band gap hexagonal boron nitride (hBN) as the tunnel barrier to preferentially transmit high-energy Auger-excited carriers to a graphite electrode. The unambiguous signatures of Auger processes are a rise in the photocurrent when excitons are created by resonant excitation, and negative differential photoconductance resulting from the shifts of the exciton resonances with voltage. We detect holes Auger-excited by both neutral and charged excitons, and find that the Auger scattering is surprisingly strong under weak excitation. The selective extraction of Auger carriers at low, controlled carrier densities that is enabled by vdW heterostructures illustrates an important addition to the techniques available for probing relaxation processes in 2D materials.

The article proposes the design of a mechanism for the extraction of sapropels in small and shallow water bodies. The mechanism allows not to dilute sapropel with water and to lift deposits of natural moisture from the bottom of the reservoir. This mechanism is easy to manufacture and operate, much cheaper than analogues, reliable in operation, mobile. Extraction of sapropels by the proposed mechanism improves the environmental performance at the extraction site, as it has a low siltation rate. To develop the design of the intake part of the mechanism, the motion of the sapropel particle during its interaction with the auger blade was analyzed. The dependences for determining the trajectory of sapropel particles in the intake part of the screw pump are theoretically derived. It is proposed to design the screw of the intake part of the mechanism so as to alternately place the intermittent blades with positive and negative values ​​of the angle of inclination of the blade to the plane perpendicular to the axis of rotation of the auger. This will allow more intensive grinding of the compacted lower layer of sapropel. It is determined that the height of the conical intake part should be 2…3 times greater than the height of the screw. In this case, the sapropel particle will not be able to bounce off the blade and out of the conical part.

Minority-carrier lifetimes and diffusion lengths have been deduced from a comparison of band structure simulations and experimental measurements on mid-wave infrared InAsSb XBn and long-wave infrared InAs/GaSb type II superlattice (T2SL) XBp barrier detectors with low diffusion-limited dark current close to mercury cadmium telluride Rule 07 and high quantum efficiency. For the XBn devices, a lifetime of 1.9 μs was observed with a corresponding diffusion length of 14.5 μm. In contrast, the T2SL exhibited a much shorter lifetime of 7.5 ns, but the diffusion length of ∼ 7 μm was long enough to ensure that almost 90% of the photocarriers are collected. The lifetime appears to be Auger limited in the case of n-type InAsSb, but for the p-type T2SL, Shockley–Read–Hall (SRH) traps appear to dominate. In the second case, possible scenarios for the dominance of SRH recombination are discussed to identify pathways for further performance optimization.

Accurate elemental quantification of materials by X-ray detection techniques in electron microscopes or microprobes can only be carried out if the appropriate mass absorption coefficients (MACs) are known. With continuous advancements in experimental techniques, databases of MACs must be expanded in order to account for new detection limits. Soft X-ray emission spectroscopy (SXES) is a characterization technique that can detect emitted X-rays whose energies are in the range of 10 eV to 2 keV by using a varied-line-spaced grating. Transitions producing soft X-rays can be detected and accurate MACs are required for use in quantification. This work uses Monte Carlo modeling coupled with multivoltage SXES measurements in an electron probe micro-analyzer (EPMA) to compute MACs for the L2,3-M and Li Kα transitions in a variety of aluminum alloys. Electron depth distribution curves obtained by the software MC X-ray are used in a parametrized fitting equation. The MACs are calculated using a least-squares regression analysis. It is shown that X-ray distribution cross-sections at such low energies need to take into account additional contributions, such as Coster–Kronig transitions, Auger yields, and wave function effects in order to be accurate.

The interatomic Auger transitions in compounds containing atomic components with core levels close in energy are studied theoretically and experimentally. The Coulomb transitions of holes between such levels lead to resonant enhancement of the Auger spectra (with respect to the energy difference between the levels). Interatomic Auger transitions involving higher levels are formed by shaking up electrons due to the dynamic field of photo-holes produced in the process of absorbing X-ray radiation and during the transition. These effects are observed experimentally in the XPS and Auger spectra of CuInSe2-type materials.

Solar cell research has always been an attraction by virtue of its clean and green status. However, to overcome the implications of high cost and moderate efficiency, there has always been fierce competition to search alternative approach for designing efficient solar cells with optimal performance-cost ratio. Recently, antimony sulfide (Sb2S3) has received substantial attention as an absorber in thin film solar cells due to earth abundance, low cost, non-toxic property and high optical absorption. Still, its performance could not match Si based cells. In this work, we adopted two-stage simulation approach to design Sb2S3 absorber based heterojunction solar cell to enhance efficiency. Initial simulation for configuration optimization was done considering thickness, defect density, recombination (radiative, Auger) effect, carrier density of the Sb2S3 absorber layer. Buffer layer thickness and absorption coefficient optimization was taken up. Further, series and shunt resistance of the device as well as conduction band offset (CBO) at absorber/buffer interface was also optimized at initial stage only. In the next level of simulation, efficiency enhancement was achieved by optimizing optimal back contact metal work function, absorber layer band gap grading and temperature. The aforesaid two-stage optimization yielded efficiency ~24.81%, which is higher than conventional thin film solar cell. The optimal solar cell structure configuration, for Sb2S3 absorber solar cell, suggested a positive CBO of 0.26 eV (e.g.; ZnS buffer layer), a back contact metal work function of 5.1 eV (e.g.; Mo, Au) and band gap grading window ~1.31 to 1.62 eV.

The Auger electron spectroscopy is an effective method to study the chemical composition of solid surfaces and near-surface layers. Sensing the Auger spectra in atomic systems and solids gives the important data for the whole number of scientific and technological applications. When considering the method principles, the main attention is given as a rule to the models for drawing chemical information from the Auger spectra and to the surface composition determination methods by the Auger spectrum decoding. It is just the two-step model that is used most widely when calculating the Auger decay characteristics. The relaxation processes due to Coulomb interaction between electrons and resulting in the electron distribution in the vacancy field have no time to be over prior to the transition. In this paper the combined relativistic energy approach and relativistic many-body perturbation theory with the zeroth order density functional approximation is applied to determination of the energy and spectral parameters of the Auger decay for the Na, Si, Ge, Ag solids. The results are compared with reported experimental results as well as with those obtained by alternative theoretical schemes. The important point is linked with an accurate accounting for the complex exchange-correlation (polarization) effect contributions and using the optimized one-quasiparticle representation in the relativistic many-body perturbation theory zeroth approximation, which significantly affects the agreement of theory and experiment.