RE-doped β-Ga₂O₃ seems attractive for future high-power LEDs operating in high irradiation environments. In this work, we pay special attention to the issue of radiation-induced defect anisotropy in β-Ga₂O₃, which is crucial for device manufacturing. Using the RBS/c technique, we have carefully studied the structural changes caused by implantation and post-implantation annealing in two of the most commonly used crystallographic orientations of β-Ga₂O₃, namely the (-201) and (010). The analysis was supported by advanced computer simulations using the McChasy code. Our studies reveal a strong dependence of the structural damage induced by Yb-ion implantation on the crystal orientation, with a significantly higher level of extended defects observed in the (-201) direction than for the (010). In contrast, the concentration and behavior of simple defects seem similar for both oriented crystals, although their evolution suggests the co-existence of two different types of defects in the implanted zone with their different sensitivity to both, radiation and annealing. It has also been found that Yb ions mostly occupy the interstitial positions in β-Ga₂O₃ crystals that remain unchanged after annealing. The location is independent of the crystal orientations. We believe that these studies noticeably extend the knowledge of the radiation-induced defect structure, because they dispel doubts about the differences in the damage level depending on crystal orientation, and are important for further practical applications.

Fe-Cr alloys serve as model alloys for the investigation of radiation induced effects in ferritic-martensitic steels which are candidate structural materials for future fusion reactors. In this work the effect of Cr segregation and/ or agglomeration in 490 keV Fe+ ion irradiated Fe-10at%Cr alloys in the form of thin films is investigated. The irradiations took place at 300 ◦C at doses ranging from 0.5 to 20 displacements per atom (dpa). Polarized Neutron Reflectivity (PNR) measurements were used for the determination of the solute Cr concentration in the Fe-Cr matrix. Cr depletion from the Fe-Cr matrix up to 2.4 at% was found. This is related to solute Cr decrement as the accumulated dose increases. After the damage of 4 dpa, solute Cr reaches the asymptotic value of 8.4 at%, close to that of the thermodynamic equilibrium in Fe-Cr. Atom Probe Tomography (APT) measurements showed that after irradiation Cr accumulates into clusters the majority of which is co-located with oxygen.

The factors that influence the formation of helium blisters in copper were studied, including crystallographic grain orientation and thermomechanical conditions. Helium implantation experiments were conducted at 40 KeV with a dose of 5 × 10¹⁷ ions/cm², and the samples were then subjected to post-implantation heat treatments at 450 °C for different holding times. A scanning electron microscope (SEM) equipped with an electron backscatter diffraction (EBSD) detector was used to analyze the samples, revealing that the degree of blistering erosion and its evolution with time varied with the crystallographic plane of the free surface in different ways in annealed and cold rolled copper. Out of the investigated states, rolled copper with a (111) free surface had superior helium blistering durability. This is explained by the consideration of the multivariable situation, including the role of dislocations and vacancies. For future plasma-facing component (PFC) candidate material, similar research should be conducted in order to find the optimal combination of material properties for helium blistering durability. In the case of Cu selection as a PFC, the two practical approaches to obtain the preferred (111) orientation are cold rolling and thin layer technologies.

Low-kV scanning electron microscopy imaging was used to visualize the 2D profiles of internal resistivity distribution in 600 keV He2+ ion-irradiated epitaxial GaAs and Al(0.55)Ga(0.45)As. The influence of the dopant concentration on DIVA (damage-induced voltage alteration) contrast formation has been studied in this paper. The threshold irradiation fluencies (the fluencies below which no damage-related contrast is observed) were defined for each studied material. The results show that the same level of damage in the material caused by ion irradiation becomes visible at lower threshold fluence in the case of lower-doped sample of the same composition. The aluminum content in the composition of materials exposed to ion irradiation and subsequent DIVA contrast formation mechanism was considered as well. The carrier concentration in irradiated layers has been studied by Raman spectroscopy and photoluminescence measurements, which confirmed that the increase of the resistivity of the material caused by ion-irradiation damage generation is resulting from the formation of deep states in the bandgap trapping free carriers.

This work aims to estimate the Curie temperature and critical exponents in the critical regime of III-V ferro- magnetic semiconductor (FS) (Ga,Mn)P film using various methods, including Arrott and Kouvel-Fisher plots, as well as electrical transport measurements. The (Ga,Mn)P film was prepared by implanting Mn ions into an intrinsic (001) GaP wafer, followed by pulsed laser melting (PLM). The magnetic properties of the (Ga,Mn)P layer were systematically investigated. The study investigated the accuracy of four different methods in deter- mining the critical behaviors for the magnetic properties close to TC. The results suggest that the critical ex- ponents are similar to those of the mean-field model, as indicated by the modified Arrot plots and temperature dependent effective critical exponents. However, the accuracy of the temperature-dependent resistance Rₓₓ(T) method and Kouvel-Fisher (K-F) analysis is limited due to the Gaussian distribution of Mn ions in the film.

This study explores the delaying of the formation of helium bubbles and blisters in pure titanium by hydrogen pre-implantation. Titanium, implanted with helium (40 KeV, 5 × 10¹⁷ ions/cm²), exhibited large bubbles that cause exfoliation after heat treatment, whereas hydrogen pre-implantation inhibited bubble growth at room temperature and reduced the exfoliation after heat treatment.
In the samples pre-implanted with hydrogen, we found evidence of helium diffusion delay by: (a) a fourfold reduction in bubble pressure (b) faceted cavities in the samples (c) a smaller increase in titanium lattice pa- rameters (d) a 16-fold reduction in average bubble size and a sixfold reduction in bubble area fraction (e) a more than twofold decrease in exfoliation (f) a tendency toward the formation of larger bubbles as a result of heat treatment. We believe that it is reasonable to assume that the inhibition of helium diffusion between tetrahedral interstitial lattice sites takes place because of the occupation of the intermediate octahedral sites by hydrogen atoms.
Evidence for the opposite effect, that is inhibition of the diffusion of hydrogen in the presence of helium, is found in the retention of hydrogen in the specimens at elevated temperatures. This retention allowed the exis- tence of titanium hydride after heat treatment at 680 °C. The present study sheds light on the intricate interplay between hydrogen and helium in titanium, providing insights into mechanisms that can potentially mitigate helium-induced damage in materials.

Carbides are known for high hardness and corrosion resistance and therefore applicable as protective coatings. C/Si and C/W multilayers (the individual layer thicknesses were between 10 and 20 nm) have been irradiated at room temperature by argon and xenon ions. The energies varied between 40 and 120 keV while the fluences were in the range of 0.07 - 6 × 10¹⁶ ions/cm². The SRIM simulation was applied to have the proper ion energy. The irradiation induced intermixing and carbide (SiC and WC) formation at the interfaces already for the lowest irradiation fluence. The component in-depth distribution has been determined by AES depth profiling which showed that it varied greatly as a function of the irradiation conditions and layer structure. In both material pair the thickness of the produced carbide increased with square root of fluence but the mixing mechanism were different: local spike for C/W and ballistic for C/Si. The mixing efficiency was lower for the C/Si than for the C/ W.

ZnO nanopillars were implanted with Au-400 keV and Ag-252 keV ions with ion fluences from 1 × 10¹⁵ cm⁻² to 1 × 10¹⁶ cm⁻². We compared ZnO nanopillars solely implanted with Au-ions and dually-implanted with Au and Ag-ions. Rutherford Back-Scattering spectrometry (RBS) confirmed Ag and Au embedded in ZnO nanopillar layers in a reasonable agreement with theoretical calculations. A decreasing thickness of the ZnO nanopillar layer was evidenced with the increasing ion implantation fluences. Spectroscopic Ellipsometry (SE) showed a decrease of refractive index in the nanopillar parts with embedded Au, Ag-ions. XRD discovered vertical domain size decreasing with the proceeding radiation damage accumulated in ZnO nanopillars which effect was preferably ascribed to Au-ions. SE and diffuse reflectance spectroscopy (DRS) showed optical activity of the created nanoparticles at wavelength range 500 – 600 nm and 430 – 700 nm for the Au-implanted and Au, Ag-implanted ZnO nanopillars, respectively. Photoluminescence (PL) features linked to ZnO deep level emission appear substantially enhanced due to plasmonic interaction with metal nanoparticles created by Ag, Au-implantation. Photocatalytic activity seems to be more influenced by the nanoparticles presented in the layer rather than the surface morphology. Dual implantation with Ag, Au-ions enhanced optical activity to a larger extent without significant morphology deterioration as compared to the solely Au-ion implanted nanopillars.

The paper describes the recovery effects of pulsed electron beam treatment in Ge single crystals implanted with various doses of Sn ions at room and low temperatures. A protective coat of 100 nm Sn was applied as a sacrificial layer. The implanted layers were studied by RBS/cRBS (Rutherford BackScattering/channeled Rutherford BackScattering) method, SIMS (Secondary Ion Mass Spectrometry) and TEM (Transmission Electron Microscopy). Defects revealed in channelled RBS spectra were analysed by McChasy code. The results show that the Sn concentration attains 1% and more with very good substitutionality. They also reveal excellent lattice recovery after e-beam melting. Suggestions are derived as regards further improvement of pulsed e-beam technique.

Nanopillars of ZnO were implanted with Au-400 keV ions at various ion fluences from 1 × 10¹⁵ cm⁻² to 1 × 10¹⁶ cm⁻² and subsequently annealed at 750 °C for 15 min in order to reduce the implantation damage and to support Au nanoparticle (NP) aggregation. It was found that implantation-induced effects and thermal effects influence the Au NP coalescence as well as the quality of the ZnO nanopillars. Rutherford Back-Scattering spectrometry (RBS) showed the broader Au-depth profiles than it was theoretically predicted, but the Au-concentration maximum agrees well with prediction taking into account the effective ZnO layer density. The implantation at the higher fluences induced the morphology modification of the nanopillar layer evidenced by RBS and scanning electron microscopy (SEM). An indirect evidence of this effect was given by optical ellipsometry due to gradual refractive index changes in the ZnO nanopillars with the increased Au-ion fluence. Optical characterization of the Au-implanted and annealed nanopillars performed by means of photoluminescence (PL) and diffuse-reflectance spectroscopy (DRS) evidenced the surface plasmon resonance (SPR) activity of the embedded Au NPs. The SPR-enhanced scattering and PL emission observed in the spectral range 500–650 nm are ascribed to Au NPs or more complex Au-clusters. In addition, the ellipsometry measurements of extinction coefficient are found to corroborate well results from DRS, both indicating increase of SPR effect with the increase of Au-ion fluence and after the post-annealing.

The damage-induced voltage alteration (DIVA) contrast mechanism in scanning
electron microscope (SEM) at low electron energy has been presented as a fast and
convenient method of direct visualization of increased resistivity induced by energetic
ions irradiation in gallium nitride (GaN). Epitaxially grown GaN layers on sapphire
covered with a metallic masks with etched windows were subjected to He 2+
irradiations at 600 keV energy. The resulting two-dimensional damage profiles at the
samples cross-sections were imaged at SEM at different e-beam energies and scan
speeds. The gradual development of image contrast was observed with the increase of
cumulative charge deposited by electron beam irradiation, to finally reach the
saturation level of the contrast related to the local resistivity of the ion-irradiated part of
GaN.
The presented method allows one to directly visualize the ion-irradiated zone even for
the lowest resistivity changes resulting from ion damage, i.e. all levels of insulation
build-up in GaN upon irradiation with ions. Taking into account that it is not possible to
apply the etch-stop technique by wet chemistry to GaN, it makes the presented
technique the only available method of visualization of highly resistant and insulating
regions in GaN-based electronic devices.
Main aim of the presented work is to get a deeper insight into a DIVA contrast in GaN
with the special emphasize to discuss the role of rastering speed and electron beam
current, i.e. details of charge build-up ion the sample surface.