Advanced Materials Research Vol. 1117

Abstract: On an example of poly(vinylidene fluoride - trifluorethylene) ferroelectric polymer we have shown how different optical methods can be applied for basic optical constants such as refractive index and absorption coefficient obtaining, scattering surface quality control, spectral transmission range control, examining polarization degree etc. Wide range of these methods can be applied not only to thin ferroelectric films but for other different samples.

Abstract: A novel approach to obtaining chlorine-silicate phosphors is developed. This method based on the synthesis in a microwave furnace is shown to provide the following advantages compared with the conventional procedures: (a) “warmer” color, (b) increased brightness, (c) significantly reduced processing time and cost. Phosphors are suitable for white LED and cathodoluminescent lamp applications.

Abstract: Polymer conductive filler composites are believed to be promising materials for flexible force sensor manufacture. Polyisoprene various carbon allotrope hybrid composites were made and their piezoresistive properties depending on the two type’s filler concentration and their ratio have been determined. Electrical resistance relaxations of hybrid composites at constant pressure in room temperature were determined as well. Experimental data of resistance relaxation was analyzed and fitted similarly to stress relaxation of polymers at constant pressure.

Abstract: In framework of methods used in nonlinear optics the output voltage of toroid transformer with soft ferrite core is calculated. It shown that apart from the fundamental frequency, it contains also harmonics of third and fifth order. An experimental verification on real transformer with MnZn ferrite core confirms the statements developed.

Abstract: Two types of single beam laser traps have been built. Laser trap using visible light is used to optically trap micro-and nanosized polymer spheres. Laser trap using near infrared radiation is used to avoid optical damage when used to manipulate living cells. Manipulation of internal organelle was successfully demonstrated.

Abstract: Molecular and lattice vibration frequencies of solid-state salicylic acid were studied in the Terahertz (THz) and Mid-Infrared (Mid-IR) ranges. The calculation of the THz and Mid-IR spectra of salicylic acid which was based on the solid-state density functional theory (DFT) was carried out. Experimental studies were conducted by THz absorbance spectroscopy and Fourier transform infrared spectroscopy (FTIR) methods. Vibrations revealed in “finger-print” spectrum of salicylic acid were compared with the typical vibrations of groups of atoms that make up organic molecules.

Abstract: At present there are many researches and forums concerning the dimensions of photon. The discussions are very active, there are many hypothesis and there is no univocal conclusion. We decided to approach the problem experimentally, trying to give an answer to the question: what is the possibly smallest size of microbore/microgap the photon can’t pass through. In these experiments the specially formed single photon beam was directed on the microstructure and the number of photons passing through was measured. Also we experimented with the photon size using Mach-Zender interferometer.

Abstract: A possibility to improve the quality of polycrystalline CdS thin film by Nd:YAG laser irradiation was shown. The CdS thin film was prepared by closed space sublimation method on ITO/glass structure and irradiated by Nd:YAG laser with intensity up to 15 MW/cm². Several evidences demonstrated the improvement of the optical properties of the CdS thin film after the laser radiation: appearance of photoluminescence band at ~2.530 eV, which is attributed to bound exciton emission; appearance of “spike” in the reflection spectrum at ~2.573 eV between upper and lower polariton branches and the increase intensity of LO phonon line at 305 cm^-1 about 3 times in Raman back scattering spectra. Moreover, the increase by 20% of the size of crystals in CdS after laser radiation takes place, which was proved by using X-Ray diffraction analysis.

Abstract: In silicon nanoscale transistors, dopant (impurity) atoms can significantly affect transport characteristics, in particular at low temperatures. Coupling of neighboring dopants in such devices is essential in defining the properties for transport. In this work, we briefly present a comparison of different regimes of inter-dopant coupling, controlled by doping concentration and, to some extent, by selective, local doping. Tunneling-transport spectroscopy can reveal the energy spectrum of isolated dopants and of strongly-coupled dopant atoms. Interactions of multiple-dopants quantum dots (QDs) and satellite individual dopant-traps, as observed in some devices, can provide further information to bridge such inter-dopant coupling regimes for more advanced applications.

Abstract: Further development of dopant-atom-based transistors requires investigation of the effects of discrete dopant distribution on device operation. Hence, it is important to monitor dopants’ arrangement inside transistor channels. We used Kelvin Probe Force Microscope (KPFM) to measure surface potential profiles of field-effect transistor (FET) channels doped with different concentrations of phosphorus atoms. We observed three basic configurations of dopants: solitary donors, “clusters” of a few coupled donors, and “clusters” of many donors. Our systematic observation provides information about the formation of quantum dots consisting of a single donor or a number of coupled donors.