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Using the method of reactive magnetron sputtering, nanostructured TiAlN coatings were formed on the substrates of AISI 304 stainless steel. The formed TiAlN coatings were irradiated with argon ions Ar+ with an energy of 200 keV in the fluence range from 2:5 × 1016 ions/cm² to 2 × 1017 ions/cm² at a temperature of 480°C. The elemental composition and structural-phase state of virgin and irradiated coatings were investigated by methods of energy-dispersive X-ray spectroscopy, scanning electron microscopy as well as X-ray phase analysis. The mechanical properties of the obtained structures were studied by nanoindentation using the Oliver and Pharr method; hardness and Young's modulus were measured. The indicators of the impact strength, as the H=E* ratio, as well as the resistance to plastic deformation, as the H³=E*2 ratio, of the coatings under study were calculated. It was found that the nanostructured TiAlN coatings retain their structure up to the irradiation fluence of 2×1017 ions/cm², at which the beginning of phase segregation of solid solution (Ti, Al)N as the main phase of the coating as well as blistering is observed. The nonlinear nature of changes in the hardness H, Young's modulus E, impact strength H=E*, and resistance to plastic deformation H3=E*2 on the irradiation fluence was found. [ABSTRACT FROM AUTHOR]

The synthesis of ZnSe nanoclusters produced by high-fluence implantation of Zn+ and Se+ ions into silica is numerically simulated. The developed model is based on solving the system of the convection-diffusion-reaction equations. The ion-beam synthesized nanoclusters were identified using the transmission electron diffraction method as ZnSe nanocrystals. According to the transmission electron microscopy data, the nanocrystal density amounts to 1:15 × 1012 cm-2, and the mean diameter is 5 nm. The fraction of the total number of implanted Se atoms bound with Zn during the formation of ZnSe nanocrystals was counted from the transmission electron microscopy images. It amounts to ~5:6 at.%. This value was used to calculate the mean values of the radiation-enhanced diffusion coefficients in the silica. For Zn atoms DZn = 1:94 × 10-16 cm²/s, and for Se atoms DSe = 2:88 × 10-16 cm²/s. A comparison of simulation results with experimental data revealed a reasonable correlation. [ABSTRACT FROM AUTHOR]

Thermal desorption spectrometry measurements of Kr implanted with energies 100 keV and 150 keV (fluence 2 × 1016 cm-2) into the Ge sample are considered. A sudden release of Kr is observed in the temperature range of 800-840 K. The very narrow peaks in the thermal desorption spectrometry spectra (width of several K) come most probably from the release of gas trapped in pressurized bubbles. Analysis of peak shifts with increasing heating rate enabled the estimation of the adsorption activation energy values of 2.5 eV and 2.3 eV for the implantation energies 100 keV and 150 keV, respectively. These values are comparable to those obtained for Ar implanted into the Ge samples and for Kr implanted into the Si samples. [ABSTRACT FROM AUTHOR]

The effect of outdiffusion of Mn interstitials from (Ga,Mn)As epitaxial layers, caused by post-growth low-temperature annealing, on their electronic- and band-structure properties has been investigated by modulation photoreflectance (PR) spectroscopy. The annealing-induced changes in structural and magnetic properties of the layers were examined with high-resolution X-ray diffractometry and superconducting quantum interference device magnetometry, respectively. They confirmed an outdiffusion of Mn interstitials from the layers and an enhancement in their hole concentration, which were more efficient for the layer covered with a Sb cap acting as a sink for diffusingMn interstitials. The PR results demonstrating a decrease in the band-gap-transition energy in the as-grown (Ga,Mn)As layers, with respect to that in the reference GaAs one, are interpreted by assuming a merging of the Mn-related impurity band with the GaAs valence band. Whereas an increase in the band-gap-transition energy caused by the annealing treatment of the (Ga,Mn)As layers is interpreted as a result of annealing-induced enhancement of the free-hole concentration and the Fermi level location within the valence band. The experimental results are consistent with the valence-band origin of itinerant holes mediating ferromagnetic ordering in (Ga,Mn)As, in agreement with the Zener model for ferromagnetic semiconductors. [ABSTRACT FROM AUTHOR]

Modulation photoreflectance spectroscopy and Raman spectroscopy have been applied to study the electronic- and band-structure evolution in (Ga,Mn)As epitaxial layers with increasing Mn doping in the range of low Mn content, up to 1.2%. Structural and magnetic properties of the layers were characterized with high-resolution X-ray diffractometry and SQUID magnetometery, respectively. The revealed results of decrease in the band-gap-transition energy with increasing Mn content in very low-doped (Ga,Mn)As layers with n-type conductivity are interpreted as a result of merging the Mn-related impurity band with the host GaAs valence band. On the other hand, an increase in the band-gap-transition energy with increasing Mn content in (Ga,Mn)As layers with higher Mn content and p-type conductivity indicates the Moss-Burstein shift of the absorption edge due to the Fermi level location within the valence band, determined by the free-hole concentration. The experimental results are consistent with the valence-band origin of mobile holes mediating ferromagnetic ordering in the (Ga,Mn)As diluted ferromagnetic semiconductor. [ABSTRACT FROM AUTHOR]

Brillouin scattering and x-ray photoelectron spectroscopy (XPS) have been utilized to characterize Ge+-implanted thermal SiO2 layers on a Si substrate with subsequent annealing at 500 °C and 1100 °C. Sputtering depth profiling in conjunction with XPS studies have been applied to identify the chemical state of elemental Ge and GeO2 precipitations in the SiO2 matrices. The presence of a subsurface GeOx zone as predicted in kinetic 3-dimensional lattice simulations has been confirmed. It is concluded that the intermediate step of Ge oxide formation seems necessary for the creation of Ge nanoclusters. The Ge atomic concentrations obtained from XPS were used to compute the bulk and shear moduli, and consequently the surface acoustic wave (SAW) velocities, for the Ge/GeO2/SiO2 systems. These calculations confirm the character of SAW velocity softening as determined from the Brillouin scattering investigations. [ABSTRACT FROM AUTHOR]

The thermal desorption spectrometry (TDS) measurements of He implanted with the energies 80 keV and 100 keV into Ge was considered. The release of the noble gas took place at temperature range 600-950 K. The TDS spectra had a form of a very wide peak consisting of two parts which means that one deals with two states of He into Ge. No surface blistering or formation of craters was observed after the annealing of the samples implanted with the fluence 1 × 1016 cm-2. the critical fluence needed for bubble formation in Ge is higher than for Si. The analysis of the peak shift with the heating ramp rate allows estimation of desorption activation energies. They are close to 0.8 eV for both peaks (100 keV) while the energy for the second peak in the case of E = 80 keV was more than twice higher. [ABSTRACT FROM AUTHOR]