Effect of Absorbing Layer Thickness on Efficiency Solar Cells Based on Cu(In,Ga)(S,Se)2

On the basis of one-dimensional model of the solar cell (SC) the influence of photoactive layer thickness on the photocurrent (a key parameter for the collection efficiency of photogenerated charge carriers) of a has been studied. It is shown that for a typical Cu(In,Ga)(S,Se)2 - based SC the optimal value of the photoactive layer thickness is about 1.5 mkm. Reducing the thickness of the photoactive layer leads to a sharp decrease in the photocurrent and increase the series resistance

Optical and photoelectrical properties of CdSxSe1–x films produced by screen-printing technology

In this paper the optical and photoelectrical properties of CdSxSe1–x films prepared using the screenprinting and sintering technique, were studied. CdCl2 was used both as a sintering flux and as a doping agent. CuCl was also used as a doping agent. The temperatures and times of preparation varied in the range of 500–600 °С and 5–60 min, respectively. The as-prepared films were characterized by the scanning electron microscopy, micro-probe X-Ray analysis, photoluminescence and photoconductance methods. Our investigations have shown that photoresponse of the CdSxSe1–x films prepared by a screenprinting method can be suitable for the production of large-area photosensitive devices

Optical Properties of Cu(In, Ga)(S, Se)2 Films for Solar Cells

In this paper, we present structural and optical properties of single-phase Cu(In, Ga)(S, Se)2 alloys, which have been prepared using a novel selenization/sulfurization growth process to react copper-indium-gallium alloy films. The grown scheme differs critically from standard two-step grown processes and was carried out without toxic H2S and H2Se gases. The calculated band gap values for layers with varying sulfur content (i.e. S/(S+Se) = 0.16 and 0.19), determined from optical transmission and reflectance measurements, were found to be 1.17 and 1.23 eV respectively. The low temperature PL measurements also confirmed the shift in the band gap of the CIGSS absorber films with sulfur incorporation. In summary, this reaction process produced single-phase CIGSS thin films with controlled sulfur amount suitable for photovoltaic application

Cadmium-free Thin-Film Cu(In,Ga)Se2(In2S3) Heterophotoelements Fabrication and Properties

The method of heat treatment of metallic Cu–In–Ga layers in the N2 inert atmosphere in the presence of selenium and sulfur vapors was used to grow homogeneous films of Cu(In,Ga)(S,Se)2 alloys onto which the CdS or In2S3 films were deposited and, on the basis of these structures, the thin-film glass/Mo/p-Cu(In,Ga)(S,Se)2/n-(In2S3,CdS)/n-ZnO/Ni–Al photoelements were fabricated. The mechanisms of charge transport and the processes of photosensitivity in the obtained structures subjected to irradiation with natural and linearly polarized light are discussed. The broadband hotosensitivity of thin-film heterophotoelements and the induced photopleochroism were detected; these findings indicate that there is an interference-related blooming of the structures obtained. It is concluded that it is possible to use ecologically safe cadmium-free thin-film heterostructures as high-efficiency photoconverters of solar radiation

Raman Study of CVD Graphene Irradiated by Swift Heavy Ions

CVD-graphene on silicon was irradiated by accelerated heavy ions (Xe, 160 MeV, fluence of 1011 cm-2) and characterized by Raman spectroscopy. The defectiveness of pristine graphene was found to be dominated by grain boundaries while after irradiation it was determined by both grain boundaries and vacancies. Respectively, average inter-defect distance decreased from ~ 24 to ~ 13 nm. Calculations showed that the ion irradiation resulted in a decrease in charge carrier mobility from ~ 4.0 × 103 to ~ 1.3·103 cm2/V s. The results of the present study can be used to control graphene structure, especially vacancies concentration, and charge carrier mobility

ИССЛЕДОВАНИЕ ТОНКИХ ПЛЕНОК Cu2ZnSnSe4 МЕТОДОМ АТОМНО-СИЛОВОЙ МИКРОСКОПИИ

In comparison to the traditional use of glass substrates, the thin films onto metal substrates offer improved device cooling, economical large-scale roll-to-roll processing, and applicability in lightweight, as well as flexible products. However, unlike glass, metal foils tend to exhibit rough surfaces. This article studies the substrate-type (Mo/glass and Мо-foil) effect on the topographic characteristics of the Cu2ZnSnSe4 films by atomic force microscopy (AFM). Cu2ZnSnSe4 thin films were prepared by the electrodeposition of stack copper/tin/copper/zinc (Cu/Sn/Cu/Zn) precursors, followed by selenization. AFM wasused to study the topographic characteristics of thin films, including grain size, surface roughness, and maximum height of the profile. It is shown that the films obtained on Mo/glass and Mo-foil substrates have similar roughness and in the both cases the grain structure is formed. The Cu2ZnSnSe4 thin films show relatively high surface roughness and maximum roughness profile height compared to Cu-Zn-Sn precursors. The increase in the surface roughness of the films was caused by the growth of grains during annealing and selenization processes.Методом атомно-силовой микроскопии исследовано влияние типа подложки на структуру и шероховатость поверхности пленок Cu2ZnSnSe4, полученных методом селенизации металлических прекурсоров Cu-Zn-Sn на подложках из стекла с подслоем молибдена и молибденовой фольги (Мо/стекло, Мо-фольга). Обнаружено, что пленки Cu2ZnSnSe4 на подложках Мо/стекло и Мо-фольга имеют близкие значения шероховатости и зернистую структуру. Пленки Cu2ZnSnSe4 имеют более высокие значения шероховатости и максимальной высоты неровности профиля, чем металлические прекурсоры Cu-Zn-Sn. Увеличение шероховатости при формировании пленок Cu2ZnSnSe4 из прекурсоров происходит за счет роста зерен в процессе отжига и селенизации

Micro Raman investigation of graphene synthesized by atmospheric pressure CVD on copper foil from decane

In this article we present the results of micro-Raman studies of graphene grown on copper foil surface by atmospheric pressure CVD using decane as precursor, nitrogen as carrier gas with zero flow of hydrogen. Analysis of Raman spectroscopy data showed that film contains spots with single layer thick graphene. We observed significant blue shift of 2D and G bands positions for mono-atomically thick graphene on copper foil. Following literature we relate this shift to the strain induced by the presence of copper substrate. Moreover, we observed changes in the defectiveness of graphene layers after the transfer, which was related to the appearance of chemically-induced defects and defects induced by changes in the mechanical strain

Technical thermodynamics.

Formation of systematic knowledge in the field of technical thermodynamic

Solid State Physics

Acquaintance with the fundamentals of solid state physic

Technical Thermodynamics of Nuclear Power Plants

Formation of systematic knowledge in the field of technical thermodynamics with reference to nuclear power installation