Effect Of Electron Irradiation Research Articles

Effect of Electron Irradiation on the Optical Properties of Zinc Oxide Powder Modified with Magnesium Oxide Nanoparticles

Effect of Electron Irradiation on the Optical Properties of Zinc Oxide Powder Modified with Magnesium Oxide Nanoparticles

In situ growth and shrinkage of coated voids in aluminium

Voids can be detrimental to the mechanical and electrical properties of materials but may also find applications in catalysis and plasmonics. Key to the performance of materials containing voids are the sizes and morphologies of the voids, which can be tuned by heat treatment. The present work investigates the morphological evolution of voids, with solute segregation at their surfaces, in an aluminium‑copper‑tin alloy during in situ heating in a transmission electron microscope (TEM). These voids exhibited complex morphological changes that included growth or shrinkage, in contrast to voids in pure Al, which all shrank and disappeared (as reported in an earlier study). Without electron irradiation, the voids never grew. Nearly one fourth of the voids grew under certain heating and electron irradiation conditions, showing distinct growth stages. Growth and shrinkage of the voids both occurred primarily along the surface of the Sn particles to which they were attached. The voids exhibited faceting as they grew and gained morphological isotropy while they shrank. The growth and shrinkage fronts were both found to be primarily the curved surfaces and not the facets at the void surfaces. Growth followed by shrinkage led to a well-defined rounded triangular shape, in projection, with smooth boundaries. This work is, to the best of our knowledge, the first to characterise the growth of nanoscale voids in aluminium using in situ heating TEM. The dual effect of heating and electron irradiation could be utilised to switch the voids between growth and shrinkage to manipulate the void size and shape. This work provides useful insights into tuning void morphologies in the development of advanced materials such as for applications in engineering, catalysis and plasmonics.

Electron irradiation effects on the optical properties of Hf- and Zn-doped β-Ga2O3

Optical and electrical properties of Hf- and Zn-doped β-Ga2O3 samples, which are n-type and insulating, respectively, were altered via high-energy electron irradiation at 2.5 or 0.5 MeV. The β-Ga2O3:Hf samples irradiated with 2.5 MeV electrons experienced a color change from blue to yellow and a large drop in conductivity, attributed to the creation of gallium vacancies, which compensate donors. This irradiation resulted in the absence of free carrier absorption and the presence of Cr3+ photoluminescence (PL). PL mapping prior to irradiation revealed optically active ZnO precipitates that formed during the growth of β-Ga2O3:Zn. These precipitates have a 384 nm (3.23 eV) stacking fault emission in the core; in the outer shell of the precipitate, the PL blue-shifts to 377 nm (3.29 eV) and a broad defect band is observed. After 0.5 MeV electron irradiation, the defect band broadened and increased in intensity. The blue PL band (435 nm) of β-Ga2O3 was enhanced for both Hf- and Zn-doped samples irradiated with 0.5 MeV. This enhancement is correlated with an increase in oxygen vacancies.

Effect of electron irradiation on microstructural evolution and mechanical properties of Sn3Ag0.5Cu solder joints

Power electronic devices face harsh radiation environments in deep space exploration. It is significant to study the reliability of solder joints of electronic devices in radiation environments. The effect of electron irradiation on the microstructure and mechanical properties of Sn3Ag0.5Cu (SAC305) Ball Grid Array (BGA) solder joints was investigated in this work. The results show that the central position of the SAC305 solder joint surface was damaged after electron irradiation. Then the surface of the solder joints was remelted. The shear strength of solder joints increases as the electron irradiation dose rises. When the electron irradiation dose reaches 80 Mrad, the shear strength of the solder joint is enhanced by 8.62% compared with that of the unirradiated sample. After irradiation, the number of dimples on the fracture surface of solder joints increases and the depth of dimples decreases. Geant4 simulation results show that the surface of solder joint is subject to more severe electron impact than the inside of solder joint is. The interaction between electrons and solder joints is the primary reason for the surface remelting of solder joints.

Characteristics of proliferation and apoptosis of hepatocytes after administration of ascorbic acid in a model of radiation hepatitis

BACKGROUND: Radiation hepatitis with the development of radiation-induced acute liver failure is considered one of the most serious complications of radiotherapy for malignant neoplasms of the liver, abdominal organs, or whole body irradiation. However, the exact mechanisms of radiation-induced liver cell death have not been fully elucidated, and therefore the study of changes in the proliferative-apoptotic ratio in liver structures remains relevant, and pre-irradiation administration of ascorbic acid can potentially protect them from the effects of electron irradiation.
 AIM: assessment of proliferation and apoptosis of hepatocytes after administration of ascorbic acid in a model of radiation hepatitis.
 METHODS: Wistar rats (Rattus Wistar; n=40) were divided into four experimental groups: I – control (n=10); II (n=10) – fractional irradiation with electrons in a total irradiation dose of 30 Gy; III (n=10) – administration of ascorbic acid before electron irradiation; IV (n=10) – administration of ascorbic acid. Animals of all groups (I – IV) were removed from the experiment a week after the last fraction. Morphological and immunohistochemical (with antibodies to Ki-67 and caspase-3) studies were carried out.
 RESULTS: A week after electron irradiation, a sharp decrease in the proportion of Ki-67-positive hepatocytes in combination with an increase in immunolabeling with antibodies to caspase-3 was observed in group II. During the administration of ascorbic acid in group III, less pronounced depth and range of liver damage was noted, confirmed by morphological and immunohistochemical methods (less pronounced decrease in the level of Ki-67 expression and an increase in the proportion of caspase-positive hepatocytes compared to the control) methods.
 CONCLUSION: An immunohistochemical study of proliferation and apoptosis of hepatocytes revealed that a week after fractional electron irradiation in SOD 30 Gy, there is a decrease in mitotic activity and an increase in cell death, and pre-irradiation administration of ascorbic acid helped level out the detected changes, which indicates its protective effect.

Degradation assessment of a single junction InP solar cell under 1 MeV electron irradiation effect

Degradation assessment of a single junction InP solar cell under 1 MeV electron irradiation effect

Incident beam current impact on space-charge retention in electron dynamitron irradiated polymethyl methacrylate

Dielectric charging aboard spacecraft and satellites is a persistent and pressing issue in materials design and applications. This study investigated the effect of electron irradiation on charge trapping and leakage properties in polymethyl methacrylate, which is necessary for determining the maximum permissible fluence of radiation before the material is pushed beyond its breakdown threshold in charged particle radiation-intense environments. It was observed that dielectric breakdown in the form of an electrostatic discharge event cannot be induced under the conditions of this experiment after an amount of time that is dependent on initial electron fluence. This time limit for which an electrostatic discharge can be induced was found to be longer for the lower beam current irradiations. The work presented here discusses the factors affecting charge leakage using a global electric field-driven model.

Unraveling the Highly Plastic Behavior of ALD‐Aluminum Oxide Encapsulations by Small‐Scale Tensile Testing

We present a study directly measuring the electron‐beam‐induced plasticity of amorphous Al2O3 coatings. Core–shell nanostructures are employed as small‐scale model systems for two‐dimensional coatings made by atomic layer deposition (ALD). Copper nanowires (NWs) are used as substrates for ALD deposition, representing a model system for interconnects commonly found in integrated circuits. Experiments are performed in situ in a transmission electron microscope (TEM) and further analyzed with electron energy loss spectroscopy (EELS). Our in situ TEM tensile experiments reveal the highly plastic behavior of the ALD shell, which withstands a maximum strain of 188%. Comparable samples under beam‐off conditions show a brittle fracture, which underlines the effect of electron irradiation. The electron‐beam‐activated bond switching within the amorphous network enables compensation of the applied tensile strain, leading to viscous flow. By incorporating an intermediate nanocrystalline layer within the Al2O3 shell, the plasticity is suppressed and brittle fracture occurs. This work directly demonstrates the tuning of mechanical properties in amorphous ALD structures through electron irradiation.

1 MeV electron irradiation effect and damage mechanism analysis of flexible GaInP/GaAs/InGaAs solar cells

In this study, the degradation behavior of flexible GaInP/GaAs/InGaAs (IMM3J) solar cells and their metamorphic subcells under 1 MeV electron irradiation was investigated. The remaining factors such as short-circuit current density (Jsc), open-circuit voltage (Voc), and maximum power (Pmax) were 95.62, 85.52, and 79.73%, respectively, at an irradiation fluence of 2 × 1015 e/cm2. The spectral responses of the InGaAs and GaAs subcells degraded significantly, and the InGaAs subcell experienced greater degradation than the GaAs subcell after irradiation. In addition, the current-limiting unit was switched from GaInP to InGaAs after irradiation. Defect analysis by deep-level transient spectroscopy (DLTS) revealed that with increasing irradiation fluence, the defects that had the greatest impact on the performance of GaAs subcells were EV + 0.36 and EV + 0.42 eV. For InGaAs subcells, the defects that had the greatest impact on the performance were EV + 0.29 and EV + 0.24 eV. The decrease in the minority carrier lifetime is the main reason for the decrease in the electrical performance of solar cells, and the variation in the effective minority carrier lifetime (τeff) in the subcells with the irradiation fluence was calculated based on the DLTS results. At a fluence of 2 × 1015 e/cm2, the τeff of the GaAs and InGaAs subcells decreased from 2.93 × 10−10 and 9.10 × 10−10 s to 1.56 × 10−11 and 1.60 × 10−12 s, respectively. These results provide a reference for predicting the degradation of short-circuit current and open-circuit voltage of flexible IMM3J.

Disentangling the Effects of Laser and Electron Irradiation on AgX (X = Cl, Br, and I): Insights from Quantum Chemical Calculations.

The effects on the lattice structure and electronic properties of different polymorphs of silver halide, AgX (X = Cl, Br, and I), induced by laser irradiation (LI) and electron irradiation (EI) are investigated using a first-principles approach, based on the electronic temperature (Te) within a two-temperature model (TTM) and by increasing the total number of electrons (Ne), respectively. Ab initio molecular dynamics (AIMD) simulations provide a clear visualization of how Te and Ne induce a structural and electronic transformation process during LI/EI. Our results reveal the diffusion processes of Ag and X ions, the amorphization of the AgX lattices, and a straightforward interpretation of the time evolution for the formation of Ag and X nanoclusters under high values of Te and Ne. Overall, the present work provides fine details of the underlying mechanism of LI/EI and promises to be a powerful toolbox for further cross-scale modeling of other semiconductors.

Effect of electron irradiation on perovskite films and devices for novel space solar cells

Perovskite solar cells (PSCs) are considered as one of the strong contenders for next-generation space solar cells due to their advantages of high efficiency, low cost, high specific power, and remarkable irradiation resistance compared with those of silicon-based and III-V compound solar cells. At present, one focuses on the irradiation effects of perovskite solar cells, but there are a few studies on the irradiation damage mechanism of the core perovskite film. To advance the spatial application of perovskite solar cells, this study conducts a comprehensive examination of the performance fluctuations exhibited by mixed-cation perovskite films and solar cells under electron irradiation. Initially, the Monte Carlo method is employed to simulate and predict the effect of electron irradiation on perovskite solar cells. Subsequently, in conjunction with the microstructure characterization and the comparison of optical/electrical performance of perovskite films before and after irradiation, the irradiation damage mechanism of film is elucidated and the electron irradiation reliability of perovskite solar cells is evaluated. The research demonstrates that mixed-cation perovskite film and solar cells exhibit outstanding resistance to electron irradiation. Even when exposed to 100 keV electron irradiation with a cumulative fluence of 5×10<sup>15</sup> e·cm<sup>–2</sup>, the PSCs maintain an average power conversion efficiency of 17.29%, retaining approximately 85% of their initial efficiency. This study provides sound theoretical and experimental evidence for designing the irradiation-resistant reinforcement of new-generation space solar cells, contributing to the improvement of their operational performance and reliability in space applications.

Electron irradiation effect on two-dimensional WSe2 phototransistors

Electron irradiation effect on two-dimensional WSe₂ phototransistors

Effect of High-Energy Electron Irradiation on the Microstructure and Properties of Polyetherimide

Effect of High-Energy Electron Irradiation on the Microstructure and Properties of Polyetherimide

Effects of electron irradiation on graphene drums

Using a scanning electron microscope, we irradiate graphene drums with electrons at an energy of 20 keV and a dosage of about 1.58 × 1017 electrons/cm2. The drums consist of graphene exfoliated in ambient air over holes having a diameter of 4.6 μm and etched into an SiO2 substrate. After irradiation, we observe that the drum’s suspended monolayer (ML) region has a ratio of the Raman D peak height, ID, to the Raman G peak height, IG, as high as 6.3. In contrast, the supported ML on the SiO2 substrate has an ID/IG ratio of 0.49. Previous studies have shown that graphene drums containing air can leak in a vacuum at a low rate. We attribute the high ID/IG ratio of the suspended ML to the air that may be in the drums. We propose that the air produces much adsorbed water on the ML, resulting in a high average defect density during irradiation. We present Raman maps of the full-width-at-half maximum, position, and height of the G, 2D, D, and D’ peaks before and after irradiation and maps of ID/IG and ID/ID’. We anneal the drums at temperatures from 50 to 215 °C and find that ID/IG significantly reduces to 0.42. The annealing data are analyzed using an Arrhenius plot. We also find that ID/ID’ depends on annealing temperature and has values ≥8, in the range expected for sp3 defects, for ID/IG ≤ 3.9. This irradiation method may help achieve high average defect densities in ML graphene, imparting novel and potentially valuable properties.

Electron Irradiation-Induced Degradation of TiN Thin Films on Quartz and Sapphire Substrates.

In this contribution, we investigated the properties of magnetron-sputtered TiN thin films on sapphire and quartz substrates before and after 5 MeV electron irradiation with a fluence of 7 × 1013 e/cm2. Structural, morphological, optical, and electrical properties were analyzed to observe the impact of electron irradiation on the TiN thin films. The results showed improved electrical properties of the TiN thin films due to high-energy electron irradiation, resulting in increased specific conductivity compared to the as-deposited thin films on both sapphire and quartz substrates. The structural features of the TiN thin films on the sapphire substrate transformed from polycrystalline to amorphous, while the TiN thin films deposited on the quartz substrate remained unchanged. Chemical state analysis indicated changes in the metallic bonding between Ti and N in the deposited TiN on the sapphire substrate, while TiN deposited on the quartz substrate retained its Ti-N bonding. This study provides insights into the effects of electron irradiation on TiN thin films, emphasizing the importance of investigating radiation resistance for the reliable operation of optoelectronic devices and photovoltaic systems in extreme ionizing radiation environments.

Effect of electron irradiation on mechanical, tribological and thermal properties of polytetrafluoroethylene

Effect of electron irradiation on mechanical, tribological and thermal properties of polytetrafluoroethylene

INFLUENCE OF ELECTRON IRRADIATION ON THE CRYSTAL STRUCTURE, SURFACE MICRORELIEF AND BANDGANP WIDTH OF THE TRIPLE CRYSTALS OF IRON DOPED MONOSELINIDE OF THALLIUM AND INDIUM

In this work, the effect of electron irradiation on the structure, surface morphology and band gap of single-and polycrystalsof iron-doped ternary crystals of thallium and indium monoselinides was investigated. It has been established that the synthesized polycrystalline samples, as well as the grown single crystals of thallium and indium monoselinides, are single-phase. The crystals have a tetragonal unit cell (space group I4/mcm) with the following lattice parameters: a ~ b = 8.12 Å, c = 6.88 Å, α=β=γ= 90°. Irradiation with electrons with an energy of 2 MeV and a beam current density of 0.085 μA/cm2leads to changes in the structure and properties of crystals in a complex manner depending on the electron fluence. Leads to a change in the parameters of the crystal lattice, an increase in the maximum value of the arithmetic mean deviation of the profile, as well as a decrease inthe height of the average surface roughness of the irradiated crystals. Irradiation of a powder sample with electrons with a fluence of 5x1016electron/cm2helps to increase the size of nanocrystallites from 32.50 nm to 43.33 nm.

Creation of NV Centers in Diamond under 155 MeV Electron Irradiation

AbstractSingle‐crystal diamond substrates presenting a high concentration of negatively charged nitrogen‐vacancy centers (NV−) are on high demand for the development of optically pumped solid‐state sensors such as magnetometers, thermometers, or electrometers. While nitrogen impurities can be easily incorporated during crystal growth, the creation of vacancies requires further treatment. Electron irradiation and annealing is often chosen in this context, offering advantages with respect to irradiation by heavier particles that negatively affect the crystal lattice structure and consequently the NV− optical and spin properties. A thorough investigation of electron irradiation possibilities is needed to optimize the process and improve the sensitivity of NV‐based sensors. In this work, the effect of electron irradiation is examined in a previously unexplored regime: extremely high energy electrons, at 155 MeV. A simulation model is developed to estimate the concentration of created vacancies and an increase of NV− concentration by more than three orders of magnitude following irradiation of a nitrogen‐rich HPHT diamond over a very large sample volume is experimentally demonstrated, which translates into an important gain in sensitivity. Moreover, the impact of electron irradiation in this peculiar regime on other figures of merits relevant for NV sensing is discussed, including charge state conversion efficiency and spin relaxation time. Finally, the effect of extremely high energy irradiation is compared with the more conventional low energy irradiation process, employing 200 keV electrons from a transmission electron microscope, for different substrates and irradiation fluences, evidencing 60‐fold higher yield of vacancy creation per electron at 155 MeV.

Fast electron damage mechanism of epoxy resin studied by electron energy loss spectroscopy and electron diffraction.

The damage mechanism and exposure tolerance of epoxy resins to fast electrons remain unclear. We quantitatively investigated the effects of electron irradiation on a common epoxy resin by dose-dependent electron energy loss spectroscopy. The results show that sp3 states of nitrogen, oxygen, and their adjacent carbon atoms were converted to sp2 states, forming imine (C=N) and carbonyl (C=O) as the total electron dose increased. The sp3 to sp2 conversion mechanism was proposed. The epoxy resin was very sensitive to fast electrons and the original electronic states were maintained up to a total dose of ∼103e-nm-2 at a low temperature of 103K. Dose-dependent electron diffraction revealed that the intra- and intermolecular geometries changed below and around the total dose of ∼103e-nm-2.

Effects of electron irradiation on analog and linearity performance of InP-based HEMT

Effects of electron irradiation on analog and linearity performance of InP-based HEMT