The model of the electro-optical effect, due to the reorientation of liquid crystal molecules from a pseudoisotropic to a homeotropic state, in a composite photonic structure with a liquid crystal filler, is elaborated. A composite (110) grooved silicon photonic structure for the middle infrared range was designed and fabricated on a silicon-on-insulator platform. Polarized reflection spectra, demonstrating the electro-optical effect, have been obtained by means of Fourier transform infrared microscopy. The relative shift of the band edge at half intensity in the region of 10μm was found experimentally to be 1.6% compared to 2.2% as predicted by theory.

The combination of titania nanofilms and silver nanoparticles (NPs) is a very promising material, with antibacterial and osseointegration-induced properties for titanium implant coatings. In this work, we successfully prepared TiO2 nanolayer/Ag NP structures on titanium disks using atomic layer deposition (ALD). The samples were studied by scanning electron microscopy (SEM), X-ray diffraction, X-ray photoelectron spectroscopy (XPS), contact angle measurements, and SEM-EDS. Antibacterial activity was tested against Staphylococcus aureus. The in vitro cytological response of MG-63 osteosarcoma and human fetal mesenchymal stem cells (FetMSCs) was examined using SEM study of their morphology, MTT test of viability and differentiation using alkaline phosphatase and osteopontin with and without medium-induced differentiation in the osteogenic direction. The samples with TiO2 nanolayers, Ag NPs, and a TiO2/Ag combination showed high antibacterial activity, differentiation in the osteogenic direction, and non-cytotoxicity. The medium for differentiation significantly improved osteogenic differentiation, but the ALD coatings also stimulated differentiation in the absence of the medium. The TiO2/Ag samples showed the best antibacterial ability and differentiation in the osteogenic direction, indicating the success of the combining of TiO2 and Ag to produce a multifunctional biocompatible and bactericidal material.

Tuning of a photonic band gap in a composite one-dimensional photonic crystal structure infiltrated with nematic liquid crystal E7 has been evaluated by simulations. It has been found that a sufficient shift of the short wavelength edge, λ edge of a main photonic band gap can be obtained in structures with a pronounced initial alignment of the liquid crystal director in the grooves of a single crystalline Si matrix. The largest effect is predicted for the reorientation of liquid crystal molecules from planar homogeneous alignment along the grooves to homeotropic alignment with respect to the Si walls due to an electro-optical effect. The shift in photonic band gap due to thermal tuning, resulting from the transition of liquid crystal from the mesophase to the isotropic phase, is less than for electric tuning. Thermo-tuning has been demonstrated experimentally.

Relationship between the rate of electrochemical formation of porous layers and the crystallographic directions of their propagation in p + -Si crystals has been studied. Results of analysis of the surface faceting revealed in the course of electrochemical etching of differently oriented cylindrical crystals are presented. A more detailed study of the anisotropy of pore growth rates has been performed for the first time by local anodization of wafers through a mask having the form of narrow long wedges which radiate from the center in all directions (wagon-wheel mask). First experiments carried out by this technique demonstrated that the orientation differences in the rate of porous layer formation are small (∼10%) and decrease in the sequence V(100) > V(112) > V(110) > V( 111). The potential of the wagon-wheel technique is analyzed as applied to the process of electrochemical pore formation. Among the technique advantages there are visualization of the etching rate distribution and simplicity in the extraction of quantitative data on the propagation anisotropy of freely moving fronts. The anisotropy-related specific features observed in local pore formation are discussed as well.