Anomalously high effective permittivity of a system of FeNi metal nanoislands

The low-frequency effective permittivity of a system of FeNi metal nanoislands was studied. It was found that the effective permittivity of the structures under study is anomalously high, 10⁷–10⁸. The nature of the high permittivity of films is caused by structural parameters (topography) of island films and is associated with the polarization of the dipoles of charged metal nanoislands.     

Nonlinear optical absorption and refraction in Ru, Pd, and Au nanoparticle suspensions

We present the results of studies of the nonlinear optical properties of Pd, Ru, and Au nanoparticles. We studied the nonlinear refraction and nonlinear absorption of suspensions of these nanoparticles at 1064-nm wavelength. A relatively strong nonlinear absorption of the Pd nanoparticles was observed in the case of 1064-nm, 50-ps pulses (β=2×10⁻⁹ m W⁻¹). The Ru and Pd nanoparticles showed weak negative nonlinear refraction (γ∼−(6–8)×10⁻¹⁶ m² W⁻¹) in this spectral range. In the case of the Au nanoparticles, a saturated absorption at 532 nm dominated over other nonlinear optical processes.     

Thermoelectric coefficient in nanoisland metallic films

We study the thermoelectric properties of island metal films on a dielectric substrate. Dependence of thermoelectric coefficient of metal films on their thickness with the dimensionless conductance $g>1$ and $g<1$ was investigated. Also, the thermopower dependence of island metal structures with $g<1$ on the chemical composition of nanostructures was studied. We found that regardless of tunneling or Drude character of conductivity, the value of the thermoelectric coefficient in island metal films is determined by the properties of film metal element.     

Detection of photoconductivity in hyperfine metal films in the visible and infrared spectral regions

Photoelectric phenomena in island metal films are investigated. The electrical conductivity and photoconductivity are measured in island films of Ti, W, FeNi, and others grown by the method of radio-frequency sputtering in argon. The photoconductivity effect is observed in metal films whose resistivity varies with temperature by the activation law of ρ ∝ exp(T₀/T)^0.5. This law is interpreted within the model of variable range hopping conductivity in the region of a Coulomb quasi-gap. The photoconductivity in metal films is detected in the visible and near-infrared spectral regions. The mechanisms of photoconductivity in an island metal film are discussed.     

Influence of ion bombardment on the profile of the depth distribution of impurity atoms in Si used for solar cells and diode structures

The chemical composition of the surfaces and surface layers of Si samples used in solar cells are studied using Auger electron spectroscopy (AES). It is shown that the low-energy implantation of Ba and O ions leads to the redistribution of impurity atoms in the surface layer and can prevent impurity atoms adsorbed onto the surface from penetrating inside the sample.     

Complexes of Chlorin e6 with Pluronics and Polyvinylpyrrolidone: Structure and Photodynamic Activity in Cell Culture

Polymeric carriers are extensively used in photodynamic therapy (PDT) for increase of efficacy of photosensitizers. Here, we report the influence of nine Pluronic copolymers on phototoxicity of chlorin e6 (Ce6), in particular 5‐ to 7‐fold rise in the phototoxicity caused by hydrophilic Pluronics F127, F108, F68 and F87 and practically no influence on Ce6 of more hydrophobic polymers. The revealed value of 0.2 mg mL^?1 of Pluronic F127 concentration sufficient for half‐of‐maximal increase of Ce6 photodynamic activity proved to be close to 0.16 mg mL^?1 inherent in well‐documented carrier poly(N‐vinylpyrrolidone) (PVP). The dissociation constants of Ce6 complexes with Pluronic F127 and PVP that were estimated from UV spectra were 0.252 and 0.036 mg mL^?1, respectively, indicating higher stability of Ce6 complex with PVP. According to the results of ¹H‐NMR studies of Ce6 complexes, the porphyrin interacts not only with hydrophobic regions but also with hydrophilic sides of both polymers.     

Electron spectroscopy of the nanostructures created in Si, GaAs, and CaF2 surface layers using low-energy ion implantation

A review of the experimental results on the study of the Si, GaAs, and CaF₂ surface layers that are created using the low-energy ion implantation is presented. Optical and electron spectroscopy and microscopy are employed in the experiments.     

Threshold Phenomena in the Spectrum of the Two-Particle Schrödinger Operator on a Lattice

Theoretical and Mathematical Physics - For a broad class of short-range pairwise attraction potentials, we study threshold phenomena in the spectrum of the two-particle Schrödinger operator...