Transport and recombination in solar cells: New perspectives

The functioning of the solar cells relies on the photo-generation of carriers in p–n junctions and their subsequent recombination in the quasi-neutral regions. A number of basic issues concerning the physics of the operation of solar cells still remain obscure. This paper reports on some unsolved basic problems, namely: a model of the recombination processes that does not contradict Maxwell's equations; the role played by space charges in the transport phenomena, and the formation of quasi-neutral regions under the presence of non-equilibrium photo-generated carriers. In this work, a new formulation of the theory that explains the underlying physical phenomena involved in the generation of a photo-e.m.f. is presented.     

Distribution and Combustion of Hydrogen and Methane Mixtures with Air in a Container with Baffles: An Investigation

Atomic Energy - Seal failure of equipment and compressed gas cylinders containing hydrogen and combustible gasses attendant in their production processes is one of the standard emergency scenarios...     

Electrically controlled light scattering in FLC cells

Abstract— Three types of light‐scattering effects distinguished by physical mechanisms were studied in detail in monomeric ferroelectric liquid‐crystal (FLC) compositions at different boundary conditions and electrical pulse regimes. The total time of the scattering switching on and switching off is less than 150, 250, and 500 μsec at ±50 V for different scattering types in helix and non‐helix FLCs. They are quite fast, and FLC cells are quite transparent and were used in a stack of 30–100 light‐scattering shutters for a volumetric screen of a 3‐D display.     

Superconductivity in single crystals of the nonperovskite-like cuprate Ba2Cu3O6−x

Spontaneous crystallization from a solution in a melt at a pressure of (0.8–1)×10⁻³ Pa was used to obtain single crystals of a new nonperovskite-like superconducting phase Ba₂Cu₃O_6−x space group P _ccm, a=13.065, b=20.654, and c=11.431 Å). The superconducting properties of the crystals were investigated by modulated microwave absorption. The superconducting transition temperatures were 5 K (sample No. 1), 7 K and 13 K (sample No. 2). The superconductivity in the Ba₂Cu₃O_6−x crystals is attributed to the presence of CuO₂ chains of edge-sharing copper-oxygen squares. Nonperovskite-like Ba₂Cu₃O_6−x crystals are a new class of one-dimensional (1D) superconductors. Pis’ma Zh. Tekh. Fiz. 23, 27–34 (December 26, 1997)     

Nonstoichiometry and solubility of impurity in In-doped PbTe films on Si substrates

The chemical quantitative composition, phase constitution, and crystal structure of doped with In lead telluride films on Si (1 0 0) or SiO₂/Si (1 0 0) substrates have been studied in this work. By EPMA and atomic absorption measurements, it has been found that the concentration of In atoms y_In varied from 0.0011 to 0.045 in these deposited Pb_1−yIn_yTe films. The results of EPMA, SEM, and X-ray diffraction (XRD) measurements show that formation of In solid solutions in lead telluride matrix revealed not only in PbTe–InTe cross-section, but in PbTe–In₂Te₃ pseudobinary system also. The results of XRD show that the lattice parameter a_PbTe of PbTeIn/Si and PbTeIn/SiO₂/Si heterostructures is described by nonmonotone function and does not obey the Vegard's law within concentration interval 0.0011y_In0.045.     

Resonance phenomena of π-mode forming in multi-element gratings

An analysis of resonances of scattering from multi-element grating formed by a finite number of resonant elements is presented. It has been shown that gratings with three and more elements on its period can support the π-mode. The π-mode of a grating is characterized by the existence of the regions in the vicinity of the grating and along its period where the electromagnetic field has opposite phases. The existence and excitation of the π-mode in finite gratings with resonant cells formed by several scatterers having open cavities have been studied. The particular case of the grating with cells formed by three identical slotted cylinders has been considered in detail. An application of gratings which support the π-mode in electron-vacuum oscillators of millimeter waves for efficient deceleration of electrons and extracting energy from electron beam is discussed.     

Concentration dependence of thermodynamic interaction parameters in a polymer-polymer-solvent system

Summary The concentration dependence of Thermodynamic Interaction Parameters is reported for the system Polystyrene (PS, M_{W 3}=4.4 · 10⁵) — Polybutylmethacrylate (PBMA, M_{W 2}=2.7 · 10⁵) — CCl₄.