Detailed investigations of the spectroscopic properties of Cr3+ ions in β-Ga2O3:0.05% Cr3+ single crystals grown by the floating zone technique have been performed in the temperature range 4.5–550 K. The luminescence of Cr3+ ions at low temperatures is due to narrow R-lines (2E → 4A2 transitions) and their vibronic sidebands, whereas the broad intense band (4T2 → 4A2 transition) dominates at temperatures above 200 K. The vibronic sidebands of R-lines with amplitude of less than 5% of the R1-line at a temperature of 4.5 K cover the region of 700–735 nm. The temperature dependences of the luminescence intensity and the decay time of Cr3+ ions indicate the same mechanism of quenching of R-line intensity and shortening of lifetime for 2E of Cr3+ ions. The temperature dependence of the R1-line decay time of β-Ga2O3:Cr3+ with maximal temperature coefficient |Δτ/ΔT| = 0.023 ms K−1 at 120 K and maximal specific sensivitity |(Δτ/ΔT)τ−1| = 0.017 K−1 at 160 K indicates an application potential of this phosphor for low-temperature fluorescence thermometry.

PACS 61.50. Ks, 61.72.Ff, 68.35.bg The deposition of Al film onto the (111) surface of a p-Si crystal was shown to induce a deformation in the near-surface layer of the latter. Provided that the crystal strain is elastic and uniaxial, the gettering of defects in the near-surface layer is observed, which is confirmed by a change in the dependence of the specimen resistance on the elastic strain magnitude. The maximum depth of the defect capture has been calculated on the basis of the energy of interaction between the deformed layer and dislocations. K e y w o r d s: uniaxial elastic strain, crystal lattice, heterostructure, epitaxial growth, gettering, Cottrell atmosphere.

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Changes of the defect structure of silicon p-type crystal surface layer under the influence of plastic deformation and high temperature annealing in oxygen atmosphere were investigated by deep-level capacitance-modulation spectroscopy (DLCMS) and IR spectroscopy of molecules and atom vibrational levels. Special role of dislocations in the surface layer of silicon during the formation of its energy spectrum and rebuilding the defective structure was established. It is shown that the concentration of linear defects (N ≥ 104 cm−2) enriches surface layer with electrically active complexes (dislocation-oxygen, dislocation-vacancy, and dislocation-interstitial atoms of silicon) which are an effective radiative recombination centers.

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In this paper technological aspects of preparation of silver nanostructures on garnet substrates and their impact on absorption and photoluminescence have been studied. For this purpose, the changes of plasmonic properties as a function of the Ag NPs preparation features, such as type of substrate material, sputtered silver mass thickness, temperature, and time of thermal treatments were shown. The plasmonic structures were prepared on single-crystalline YAG and GGG garnets as well as amorphous glass substrates by the magnetron sputtering technique. Nucleation and growth of Ag nanoparticles were controlled by a thermal annealing process. Two broad absorption bands peaked at 350-370 nm and 440-650 nm were observed due to quadrupole and dipole modes, respectively, of surface plasmon resonance (SPR) of Ag nanoparticles. Changes of the positions, intensities, and widths of these absorption bands related to the nanoparticle sizes, densities, and shapes are presented. Degradation of the plasmonic structures at ambient conditions, which is revealed as diminishing of the plasmonic absorption bands and associated with sulphidation of Ag nanoparticles in the natural environment, was studied in details. Theoretical simulations of the sulphidation process modelled as coating of Ag nanoparticles with silver sulphide (Ag 2 S) film confirm the experimentally observed diminishing of SPR.

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