Sample records for oyogata shinkozo usumaku
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Energy Technology Data Exchange (ETDEWEB)
NONE
1998-03-01
Research and development was performed with an objective to manufacture amorphous silicon and thin film poly-crystal silicon hybrid solar cells with large area and at low cost, being a high-efficiency next generation solar cell. The research was performed based on a principle that low-cost substrates shall be used, that a manufacturing process capable of forming amorphous silicon films with large area shall be based on, and that silicon film with as thin as possible thickness shall be used. Fiscal 1997 has started research and development on making the cells hybrid with amorphous silicon cells. As a result of the research and development, such achievements have been attained as using texture structure on the rear layer in thin poly-crystal silicon film solar cells with a thickness of two microns, and having achieved conversion efficiency of 10.1% by optimizing the junction interface forming conditions. A photo-deterioration test was carried out on hybrid cells which combine the thin poly-crystal silicon film cells having STAR structure with the amorphous silicon cells. Stabilization efficiency of 11.5% was attained after light has been irradiated for 500 hours or longer. (NEDO)
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Energy Technology Data Exchange (ETDEWEB)
NONE
2000-03-01
Developmental research has been performed on large-area low-cost manufacturing technologies on hybrid thin film solar cells of amorphous silicon and poly-crystalline silicon. This paper summarizes the achievements in fiscal 1999. The research has been performed on a texture construction formed naturally on silicon surface, and thin film poly-crystalline silicon cells with STAR structure having a rear side reflection layer to increase light absorption. The research achievements during the current fiscal year may be summarized as follows: the laser scribing technology for thin film poly-crystalline silicon was established, which is important for modularization, making fabrication of low-cost and large-area modules possible; a stabilization efficiency of 11.3% was achieved in a hybrid mini module comprising of ten-stage series integrated amorphous silicon and thin film poly-crystalline silicon; structures different hybrid modules were discussed, whereas an initial efficiency of 10.3% (38.78W) was achieved in a sub-module having a substrate size of 910 mm times 455 mm; and feasibility of forming large-area hybrid modules was demonstrated. (NEDO)
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Energy Technology Data Exchange (ETDEWEB)
NONE
1999-03-01
The project aims to manufacture the above for the development of low-cost high-efficiency practical cells. Technologies were developed to homogeneously fabricate films with an average efficiency of 10% or more in a 100mm times 85mm area in a STAR (naturally surface texture and enhanced absorption with a back reflector) structure thin-film polycrystalline silicon (poly-Si) solar cell. The texture shape was improved for a higher light trapping effect and a STAR structure cell highly sensitive to long wavelengths and fit for use for a hybrid cell bottom layer was obtained. Various cells were examined for temperature characteristics, and it was found that thin-film poly-Si cells present a temperature coefficient equal to or less than that of bulk single-crystal silicon systems, and hybrid cells a temperature coefficient similar to that of a-Si systems. The technology was applied to a hybrid solar cell in which an a-Si cell was placed on STAR structure thin film poly-Si cells, and a resultant 3-layer a-Si/poly-Si/poly-Si cell exhibited a stabilization factor of 12.0% after 550 hours of optical irradiation. (NEDO)
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Energy Technology Data Exchange (ETDEWEB)
NONE
1999-03-01
An acorn type concentrator is a 2-dimensional system and realizes relatively high magnification power, but it requires a special assembly process for modularization because the cells and the concentration system are quite small. Under the circumstances, studies are conducted on a prism array concentrator (PAC) which will demand a smaller burden for modularization. A PAC system is basically a 1-dimensional concentrator in terms of light collection performance. The cell to be attached to one plane in the longitudinal direction of the long triangular prism is so small as 5mm in width, yet it may be as long as 50-100mm, and the conventional flat plate assembly process may be made use of. A concentration efficiency of 82% and a conversion efficiency of 10.9% were obtained from a minimodule with a light intercepting area of 5cm times 4cm. Furthermore, a conversion efficiency of 19.7-21.4% was obtained when a small 5mm-wide cell applicable to a PAC type concentration was used. Since a prism type concentrator optical system will cost much for its molding and strengthening when it is built of glass, inexpensive EVA (ethylene-vinyl acetate copolymer) was utilized as an adhesive filler. (NEDO)
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Energy Technology Data Exchange (ETDEWEB)
NONE
1998-03-01
A thin film single crystal silicon solar cell module is developed, in which a porous silicon layer is formed on the surface of a long-sized single crystal silicon substrate, a single crystal silicon film is integrated on the layer by epitaxially growing the film thereon to form a solar cell, and the solar cell is peeled off from the silicon substrate and transferred to a plastic film substrate. The achievements during this fiscal year may be summarized as follows: simultaneous formation of a porous silicon layer on a silicon substrate, reduction of anode formation current density from 200 mA/cm{sup 2} to 10 mA/cm{sup 2}, development of a silicon epitaxial device using a carbon heater, and attainment of aperture conversion efficiency of 11.8% in a thin film single crystal silicon solar cell. Three kinds of methods were developed to peel off the solar cell. A method was developed to grind silicon substrate surface from which the solar cell has been peeled off. A technology was developed to obtain a long-sized silicon substrate of about 30 cm times 10 cm times 0.1 cm from a 4-inch silicon ingot by using a wire saw. (NEDO)
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Energy Technology Data Exchange (ETDEWEB)
NONE
1998-03-01
These technological developments are intended to demonstrate module efficiency of a micro light collection type solar cell of 15% by fiscal 2000, and obtain prospect on the module manufacturing cost of 140 yen per watt. Discussions given during fiscal 1997 are as follows: development has been performed on a design method to decide construction of a non-tracking micro light collection type module; in the state of cells being integrated on the module, the cells are arranged minutely and discretely, whereas, with discussions on a method to form them and assessment of the optical system as the main objective, single crystal silicon solar cells with a size smaller than 5 mm were fabricated on a trial basis; problems of forming micro cells by using the wafer cutting process were clarified; micro cells operating on light collection were fabricated trially to extract technological problems in light collecting operation and discuss technical problems in mass production; and development was performed on an evaluation method to analyze the cells' light collecting operation, and discussions were given on a method to estimate power generation amount from the light collection type modules. (NEDO)
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Energy Technology Data Exchange (ETDEWEB)
NONE
2000-03-01
With an objective to develop low-cost and high-efficiency hybrid thin film/sheet solar cells, research and development has been performed. This paper summarizes the achievements in fiscal 1999. The research is related to a hybrid construction, in which the upper cells of amorphous silicon thin film are formed on the lower cells bonded with micro-crystalline silicon thin film relative to a poly-crystalline silicon sheet. In the technology to form the upper cells, a pin-construction using amorphous silicon thin film made by using the plasma CVD process was adopted, whereas an open circuit voltage of 1.45V, a short circuit current of 13.6 mA/cm{sup 2}, and a conversion efficiency of 13.5% were obtained. In the technology to form the substrate for the lower cells, formation of flat silicon thin plate that can be peeled off was identified as a result of adopting the construction in which a graphite substrate is provided on a rotating cooling body of 12-prism type. With regard to the technology to bond and form the lower cells, electrical properties of hetero-bonded cells were discussed, and an open circuit voltage of 0.605V and a conversion efficiency of 14.3% were obtained as a result of enhancing the film quality and optimizing the film thickness. (NEDO)
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Energy Technology Data Exchange (ETDEWEB)
Yoshimura, K; Miki, T; Tazawa, M; Jin, P; Igarashi, K; Tanemura, S [National Industrial Research Institute of Nagoya, Nagoya (Japan)
1997-11-25
In order to search for the coloration and bleaching mechanism of niobium oxide, considerations were given on optical properties and electron conditions in niobium oxide thin films (glass plates as substrates coated with ITO) prepared by using the reactive DC magnetron sputtering process. The films were so grown that their thickness will all be 100 nm to facilitate data comparison. Coloration and bleaching of the grown test films were conducted by cyclic voltammetry. Electron spectra were measured by using XPS, and electron energy was analyzed. Coloration of niobium oxide occurs as a result of change in valency electron state from an Nb {sup 5+} state to an Nb {sup 4+} state, while change in the XPS spectra also corresponds with the above change. However, the XPS spectra differ greatly between crystalline samples and amorphous samples. The coloration and bleaching mechanism of the crystallized Nb2O5 film can be explained by a reaction formula similar to that for WO3. However, with regard to the amorphous Nb2O5 film, an independent reaction involving water in the film seems to occur together with the same reaction as in the crystallized film. 9 refs., 5 figs.
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Energy Technology Data Exchange (ETDEWEB)
Tatsuta, M [New Energy and Industrial Technology Development Organization, Tokyo (Japan)
1994-12-01
This paper reports the study results on the fabrication technology of thin film polycrystalline Si solar cells in fiscal 1994. (1) On the fabrication technology of high-quality Si thin films, the new equipment was studied which allows uniform stable melting recrystallization over a large area. The new equipment adopted a heating method based on RTP system, and is now under adjustment. (2) On the fabrication technology of light/carrier confinement structure, degradation of hydrogen-treated thin film Si solar cells by light irradiation was examined. As a result, since any characteristic degradation was not found even by long time light irradiation, the high quality of the cells was confirmed regardless of hydrogen-treatment. Fabrication of stable reproducible fine texture structure became possible by using fabrication technology of light confinement structure by texture treatment of cell surfaces. (3) On low-cost process technology, design by VEST process, estimation of cell characteristics by simulation, and characteristics of prototype cells were reported. 33 figs., 1 tab.
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Energy Technology Data Exchange (ETDEWEB)
NONE
1998-03-01
Fiscal 1997 is the first year of another 4-year-long research and development phase. In addition to researches for improving on thin-film polycrystalline Si cell efficiency that have been under way, new efforts are started, which include the development of practicality-conscious thin film producing technologies aiming at higher throughput and yield and the development of modularization process technologies which are necessary for putting thin-film cells to practical use. Concerning the formation of a power generation layer on a polycrystalline Si thin film formed by the ZMR (zone-melting recrystallization) process, studies are conducted for improvement on its throughput and yield using a new CVD (chemical vapor deposition) unit. A method of modularization is evaluated, which involves a laminate of a thin-film cell attached to a resin-coated, reinforced glass substrate and an EVA (ethylene vinyl acetate) back film. A remarkable achievement is earned toward the practicalization of technologies of thin film formation enhanced in quality and throughput and technologies of thin film modularization. (NEDO)
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Energy Technology Data Exchange (ETDEWEB)
NONE
2001-03-01
For the purpose of realizing low cost and high efficiency hybrid thin films/sheet solar cells, the R and D were carried out, and the FY 2000 results were reported. As to the formation technology of the upper cell, the following technologies were developed and the results contributory to the heightening of efficiency were obtained: technology for improvement of cell characteristics by gap widening of p layer, technology for optimization of formation conditions of i layer corresponding to the hybrid solar cell, technology for heightening of current by the intermediate ZnO layer just under the upper cell. Relating to the development of formation technology of high quality microcrystal thin films, it was indicated that the microcrystal silicon thin film had the conformity effective also for polycrystal silicon, and at the same time, the conversion efficiency of 12.8% and release voltage of 0.579V were obtained by the cell using the cast polycrystal board. In the thin film/polycrystal sheet hybrid solar cell in which all these technologies were integrated, the conversion efficiency of 12.0% was achieved, and the possibility was verified of achieving the target efficiency of 14% by further improvement of FF. (NEDO)
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Energy Technology Data Exchange (ETDEWEB)
NONE
2000-03-01
Research and development has been performed on a high throughput forming technology and a modularization technology for thin film poly-crystalline solar cell modules. This paper summarizes the achievements in fiscal 1999. In developing the high throughput forming technology for a high-quality thin film, research has been made on a low-cost VEST process to re-utilize substrates by separating the thin film from the substrate. In the melting re-crystallization process, it was discovered that plasticity deformation of the substrate can be reduced greatly by raising the substrate heating temperatures. It was also found out that substrate warping amount can be reduced to about one-fifth of the conventional amount by making the thickness greater than 1.5 mm and raising the heating temperatures higher than 1300 degree C. In developing the thin film modularization technology, it was indicated that the property improving effect remains the same even if the hydrogen passivation method is changed from the hydrogen ion injection to the hydrogen plasma processing. In the trial fabrication of the thin film modules, a conversion efficiency of 13.1% was achieved in nine-cell structured modules. (NEDO)
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Energy Technology Data Exchange (ETDEWEB)
NONE
1999-03-01
The aim is to realize the practical application of the above-named solar module expected to exhibit higher efficiency and reliability and achieve cost reduction through consumption of less materials. In fiscal 1998, 1) technologies were developed to reduce substrate warpage during recrystallization for the higher-throughput fabrication of high-quality thin films and 2) technologies were also developed for the realization of higher-throughput fabrication of thin films and for efficiency improvement for thin-film modules. Under item 1), experiments were conducted by simulation for reducing warpage to occur in thin-film polycrystalline Si substrates during fabrication by melting and recrystallization. Under item 2), for the development of thin-film cell high-throughput technologies, studies were started on a more practical hydrogen plasma process to challenge the conventional process of crystal defect inactivation by hydrogen ion injection with which achievement of high throughputs is difficult. For the development of technologies for the enhancement of thin-film module efficiency, efforts were exerted to realize a 10cm times 10cm square shape for the enhancement of efficiency in the process of filling modules with cells. These efforts achieved a great step toward future practical application. (NEDO)
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Energy Technology Data Exchange (ETDEWEB)
Suzuki, M; Watanabe, S; Yoshimura, N [Akita Univ., Akita (Japan); Fujita, H [The University of Tokyo, Tokyo (Japan)
1992-12-20
Discussions were given on measurements of coefficients for static friction between different types of thin films. A small light-weight mover of a millimeter size was driven electrostatically to measure friction in a condition close to operation of a micromachine. The thin film materials were fabricated using a sol-gel process, sputtering, vacuum deposition and a CVD process. The materials include Ni, Ti, Al, SiO2, SiNx, Si wafers and glasses. The measured values for Ni-Ni, Al-Al and Ni-Al were larger by from 0.1 to 0.2 than values for bulk. The reason for this would be because of the friction generating mechanisms being different and the sample weight being lighter. Measured values for different types of thin films on silicon wafers were higher. This may be because OH groups are formed on the wafer surface causing high adhesiveness. Values for glasses are small in general. Friction coefficients for SiO2 thin films are small on the whole. However, SiO2-SiO2 showed larger values. This indicates that SiO2 is a useful material for micromechatronics, but proper selection of contacting opponents is important. 7 refs., 4 figs., 7 tabs.
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Energy Technology Data Exchange (ETDEWEB)
NONE
1999-03-01
Creation of inorganic thin films and fine particles under a microgravity atmosphere is studied, for which Japan Microgravity Center's drop test facilities are used. The Cu anodic dissolution tests are conducted using a quasi-two-dimensional electrolytic cell, as part of the basic researches on micromachining for controlling high aspect ratio and shape anisotropy. It is difficult to control natural convection on the ground, even when the electrode thickness is decreased to 100 {mu}m or less. Concentration of the electrolytic solution over the anode surface is more supersaturated under a microgravity than on the ground. For production of fine glass particles, the liquid phase is involved between evaporation and solidification of glass. The Pb-X and Pb-Zn-X systems are molten, and dropped and, at the same time, solidified by quenching. The X component (including Zn) is uniformly dispersed under a microgravity in spheres of several to 20 {mu}m in diameter, although it is separated on the ground. The spherical droplets of GaSb can grow into a single crystal even in the absence of the seed, when supercooled and directed at high speed onto silica glass. A SiGe film with fine voids can be prepared and fast adhered to the base by flash lamp annealing, when it is deposited on the base with a SiN film as the buffer and then made into the film. (NEDO)
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Energy Technology Data Exchange (ETDEWEB)
Tatsuta, M [New Energy and Industrial Technology Development Organization, Tokyo (Japan)
1994-12-01
This paper reports the survey results on the technological trend, safety and latest technologies of thin film solar cells in fiscal 1994. As the fabrication technology for amorphous film solar cells, three-electrode plasma CVD was surveyed as fabrication method for high-mobility materials, and hydrogen radical CVD as fabrication method for high-photostable films. Current foreign and domestic reliability tests were surveyed for reliability evaluation of solar cells. In order to ascertain the performance, efficiency, physical properties and optimum structure of polycrystalline Si thin film solar cells, previously reported test results on physical properties such as carrier concentration, carrier lifetime and mobility of films were surveyed together with device simulation results. In addition, technologies for high-efficiency CuInSe2 system and CdTe system solar cells, technologies for cost reduction and mass production, and environmental influence were surveyed. Estimation of production costs for cell modules, and safety of thin film solar cells were also surveyed.
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Energy Technology Data Exchange (ETDEWEB)
Nishide, T [Nissan Motor Co. Ltd., Tokyo (Japan); Mizukami, F [National Chemical Laboratory for Industry, Tsukuba (Japan)
1992-09-01
In order to control optical properties of TiO2 thin films, the TiO2 films were prepared by the sol-gel method using glycols or their ether derivatives as organic ligands to study the effect of the organic ligands on the refractive indices and crystal phases. Samples were prepared as follows: Organic ligand was added into the ethanol solution of Ti(O-iso-pr) 4, and aqueous nitric acid solution was added after reflux, and sol obtained by subsequent reflux was applied on soda lime glass or silicon wafer substrates, which were baked at 400 to 900 centigrade. Three kinds of ligand such as 2-(2-methoxyethoxy) ethanol were used. Measured items are the film thickness, thermal characteristics, crystal phase and refractive indices of thin films. The key points are as follows: In case of TiO2 thin films on the soda lime glass substrate, the changing pattern of refractive indices by temperature changes with the kind of ligand used and further the peak strength of anatase changes with the kind of ligand used. In case of silicon wafer substrates, the peak strength of anatase and rutile changes with the kind of ligand. The refractive indices and crystal phase can be controlled by properly using the ligand. 7 refs., 11 figs.
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Energy Technology Data Exchange (ETDEWEB)
Hijikata, K; Inoue, T; Nagasaki, T; Suzuki, Y; Sato, I [Tokyo Institute of Technology, Tokyo (Japan); Nakabeppu, O [The University of Tokyo, Tokyo (Japan). Faculty of Engineering
1997-02-01
This paper describes laser irradiation and velocity selective deposition experiments for fabricating high quality thin films. For the formation of Ag thin film by vacuum deposition method, YAG laser was irradiated to atoms or clusters parallel or perpendicular to the NaCl single crystal substrate, to deposit them on the substrate. For another experiment, Ag atoms selected in the given velocity were deposited on the (001) NaCl substrate by passing the molecular beam through the velocity selector. When laser was not irradiated, the thin film showed a random structure. Epitaxial growth was accelerated by the laser irradiation. When the selective velocity was set in 353 m/s at the constant intensity of molecular beam, the diffraction pattern of the thin film showed net pattern. When the selective velocity was set in 529 m/s, a structure in which ring pattern was overlapped on the net pattern was obtained. 2 figs.
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Energy Technology Data Exchange (ETDEWEB)
Shimizu, T [Kanazawa University, Ishikawa (Japan). Faculty of Engineering
1994-12-01
Described herein are the results of the FY1994 research program for development of novel technologies for fabrication of high quality thin films of silicon for solar cells. The study on the mechanisms and effects of chemical annealing reveals that the film structure greatly varies depending on substrate temperature during the hydrotreatment process, based on the tests with substrate temperature, deposition of superthin film (T1) and hydrotreatment (T2) as the variable parameters. Chemical annealing at low temperature produces a high-quality a-Si:H film of low defect content. The study on fabrication of thin polycrystalline silicon films at low temperature observes on real time the process of deposition of the thin films on polycrystalline silicon substrates, where a natural oxide film is removed beforehand from the substrate. The results indicate that a thin polycrystalline silicon film of 100% crystallinity can be formed even on a polycrystalline silicon substrate by controlling starting gas composition and substrate temperature. The layer-by-layer method is used as the means for forming the seed crystals on a glass substrate, where deposition and hydrotreatment are repeated alternately, to produce the thin crystalline silicon films of high crystallinity. 3 figs.
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Energy Technology Data Exchange (ETDEWEB)
NONE
1998-03-01
Since ion implantation causes material degradation by formation of crystalline defects, and hydrogen embrittlement deteriorates material strength, reduction of such defects has been positively studied. Study was made on a new active application of hydrogen separation into ion implantation defects. After H ion implantation of a proper depth into single-crystalline Si and SiC and successive annealing, single-crystalline films of sub-micron to several micron thick were obtained by hydrogen-induced delamination at the implantation depth due to hydrogen embrittlement in crystalline defects. The implantation depth is dependent on implantation energy. H atom forms (111) face defect through connection with dangling bond of crystalline defects. This crystal face defect forms a delamination plane through (100) face cleavage. This hydrogen embrittlement delamination by ion implantation is applicable to production of light-weight high-efficiency single-crystalline Si solar cells, and large single-crystalline SiC wafers as new resource saving process. 33 refs., 19 figs., 2 tabs.
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Energy Technology Data Exchange (ETDEWEB)
Tabata, H.; Kawai, T. [Osaka University, Osaka (Japan)
1997-08-20
The unique advantage of the pulsed laser deposition is its ability to produce highly oriented stoichiometric films at a low substrate temperature. Ferroelectric PbTiO3 thin films have been formed using 2nd laser assisted laser ablaion technique at low temperature, i.e., 350degC, on Sr7iO3 single-crystal substrates and Pt/MgO electrodes. The second laser irradiation at the substrate surface is quite effective for crystallization of the films at low substrate temperature below 400degC. The suitable energy density (fluence) of the irradiation laser is in the range of 30-100 mJ/cm{sup 2}. X-ray diffraction patterns of PbTiO3 thin films show c-axis orientation, with a rocking angle of 1.0 - 0.5deg. These films exhibit ferroelectric hysteresis loop. The dielectric constant and remanent polalyzation of the PbTiO3 films are in the range of 120-150 and 60-80 {mu}C/cm{sup 2}, respectively. 31 refs., 10 figs., 1 tab.
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Energy Technology Data Exchange (ETDEWEB)
NONE
2001-03-01
For the purpose of developing the application type new structure thin film solar cell that is low-cost, high-efficient and practical, a developmental study was made of production technology of amorphous silicon/thin film polycrystal silicon hybrid thin film solar cells, and the FY 2000 results were reported. In the study of the heightening of efficiency of the small area hybrid cell, a structure was adopted in which a transparent intermediate layer was installed between a-Si cell and bottom poly-Si cell, and the initial efficiency of 14.0% was obtained in the small area cell 1cm square. As to the large area hybrid module, the initial efficiency of 11.7% and maximum output of 44.9W were achieved in the large area substrate module with a size of 910 x 455mm. In the indoor/outdoor evaluation of the output of hybrid modules, conducted were the outdoor measurement and the output measurement made every season under the mock spectral light in two-light simulator. In summer, F.F. was improved by spectral gain and anneal effect, and the effective output about 8% higher was recognized in the module after stabilization. (NEDO)
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Energy Technology Data Exchange (ETDEWEB)
Hasegawa, H [Hokkaido University, Sapporo (Japan). Faculty of Engineering
1994-12-01
This paper reports the result obtained during fiscal 1994 on characterization and control of surface/interface recombination velocity of crystalline silicon thin films. To optimize design and manufacture of solar cells, it is necessary to identify correctly resistance factor (or doping) of bulk of materials, bulk minority carrier life, and recombination velocity on surface, passivation interface and electrode interface. A group in the Hokkaido University has been working since a few years ago on development of non-contact and non-destructive photo-luminescence surface level spectroscopy (PLS{sup 3}). A new non-contact C-V method was also introduced. Using these methods, basic discussions were given on possibility of separate measurements on surface/interface and bulk characteristics of solar cell materials. The PLS{sup 3} method and the non-contact C-V method were used for experimental discussions on evaluation of silicon mono-crystalline and poly-crystalline materials. Discussions were given on separate evaluations by using the DLTS method. 10 figs., 2 tabs.
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Energy Technology Data Exchange (ETDEWEB)
NONE
1999-03-01
The project aims to establish a manufacturing process that enables both high-quality CuInSe{sub 2} (CIS) film solar cell enlargement and cost reduction and to develop a device structure which uses less heavy metal for the purposes of increasing the CIS thin-film solar cell size and efficiency and decreasing environmental impact. Several element technologies have been established for increasing the area of high-efficiency Cu(In, Ga)Se{sub 2} (CIGS) solar cells. Concerning the enlargement of the photoabsorption layer which is to assume the most important role, it is found that a high-quality CIGS film, which is near homogeneous though within a 10cm times 10cm area, is fabricated by an in-line vapor deposition method. As for dead area reduction and high-speed patterning, it is found that laser scribing works effectively in the patterning of the window layer and photoabsorption layer. As for reduction in the use of heavy metal, a high efficiency of 16.2% is attained in a cell not using a CdS film as expected in the case of a cell using a CdS film, this thanks to a CIGS film surface reforming technique. The technique of junction formation for CIGS solar cells is improved, and then a true efficiency of 18.5% is achieved. (NEDO)
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Energy Technology Data Exchange (ETDEWEB)
NONE
1999-03-01
This research aims to achieve a conversion efficiency of 13% and a manufacturing cost of 140 yen/Wp with a 30cm times 30cm Cu(InGa)Se{sub 2}-based thin-film solar cell submodule. Ga and sulfur are combined and a film fabrication technology was developed which would improve on Voc. Concerning Ga, a laminated precursor layer was fabricated and evaluated, which comprised a Cu-25wt%Ga alloy layer and a Ga source which was a Cu-48%Ga alloy layer. Concerning sulfur, the vapor phase selenization temperature and the selenization retention time in an H{sub 2}Se gas atmosphere was allowed to vary for a change in Cu(InGa)Se{sub 2} calcopyrite crystallinity for the study of relations between the amount of sulfur taken in and the solar cell characteristics, and the relations were assessed by EPMA (electron probe microanalyzer). Technologies were developed for the fabrication of high-resistivity buffer layers by solution growth, for the fabrication of window layers (transparent, conductive ZnO film) by sputtering, and for their patterning. Submodules of a ZnO/Zn(O,S,OH)x/Mo structure were fabricated, 10cm times 30cm and 30cm times 30cm in size. The former achieved 12.5% in conversion efficiency, and the latter 11.6%. (NEDO)
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Energy Technology Data Exchange (ETDEWEB)
NONE
2000-03-01
Research and development has been performed on a technology to manufacture CIS-based thin film solar cells. This paper summarizes the achievements in fiscal 1999. In the research of a large-area light absorbing layer manufacturing technology, investigation was made on light absorbing layers in manufacturing sub-modules with a size of 30 cm times 30 cm. With regard to the temperature condition in the light absorbing layer forming process, it was found that the cooling rate affects particularly the adhesion in the connecting interface of the light absorbing layer and the Mo rear electrode layer. In addition, it was revealed that the sulfur take-in amount can be increases by extending the retention time at the sulfurizing temperature and by decreasing the temperature to turn the gas phase into selenium. In the research of elementary technologies to establish the mass production process, developments were performed on the high-resistance buffer layer manufacturing technology, the high-quality window layer film manufacturing technology, and the technology to manufacture rear electrode layer made of high-quality metals. In developing the patterning technology, two kinds of the existing patterning devices were modified and adjusted for patterning the substrates with a size of 30 cm times 30 cm. In addition, a processing device was installed in the conventional manually operated process for module finishing. (NEDO)
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Energy Technology Data Exchange (ETDEWEB)
NONE
1998-03-01
Research and development was made with an objective to achieve conversion efficiency of 13% in a 30 cm times 30 cm size submodule of a CIS-based thin film solar cell, and to develop a manufacturing technology that can achieve 140 yen/Wp. This paper describes the achievements attained during fiscal 1997. In fiscal 1997, based on the achievements reached during the previous year, a submodule with a size of 10 cm times 30 cm was fabricated for an attempt of improving the open voltage and short circuit current density. Simultaneously, the applicability thereof to a module with an area as large as 30 cm times 30 cm was evaluated. As a result of experimental discussions, enhancement in the open voltage was verified by increasing amount of Ga or sulfur, but it was not possible to achieve 600 mV or higher. In the research of component technologies to establish a mass production process, research and development was made on a high-resistance buffer layer film forming technology, a high-quality window layer film forming technology, a high-quality metallic rear electrode film forming technology, and patterning technologies. The outdoor exposure test was continued on laminated mini-modules with a size of 10 cm times 10 cm. (NEDO)
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Energy Technology Data Exchange (ETDEWEB)
NONE
1975-05-30
This research includes (1) basic study on formation technology of Si thin film crystals by particle acceleration growth, (2) basic study on junction formation technology for Si thin film crystals, and (3) basic study on GaAs compound semiconductors by pyrolysis method. In the 1st research, the thin film formation equipment was prepared for formation of charged Si particles from monosilane and solid Si in inert gas plasma by high-frequency excitation, and its expected characteristics were confirmed through its operation test. Basic data of Si thin films were also obtained by electron beam diffraction and Auger electron spectroscopy. In the 2nd research, study was made on junction formation systems for thin films, and the idea of a continuous thin film formation system was obtained for junction formation. In the 3rd research, development of p-type GaAs epitaxial technology was promoted, and it was confirmed that various p-type GaAs compound semiconductors of 10{sup 12}-10{sup 18}cm{sup -3} in impurity concentration are obtained by controlling a ratio of trimetylgallium gas to arsine gas. (NEDO)
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Energy Technology Data Exchange (ETDEWEB)
NONE
1977-03-01
This report describes the fiscal 1976 research result on production of Si thin film crystals and cell composition for photovoltaic power generation. In study on improvement of the crystallinity of polycrystal thin films by zone melting, flat recrystallized film was obtained by passing Si film through a high-frequency furnace at nearly 3mm/min in speed after growth of polycrystal Si film of 120-250{mu}m in thickness on a graphite substrate by gas-phase chemical reaction. In study on cell composition, as technology for forming electrodes on an uneven polycrystal surface with shallow junction, a Ti-Ag double layer method was developed in which junction characteristics are unaffected by heat treatment within 550 degrees C. On the photoelectric conversion efficiency of thin film cells, the efficiency of 5% and area of 10cm as targets in fiscal 1976 were attained by using a graphite substrate or polycrystal Si substrate. The thin film cell formed on an Si substrate could operate a small fan or a desk clock enough by scattered solar radiation. (NEDO)
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Energy Technology Data Exchange (ETDEWEB)
NONE
1975-05-28
This research aims at development of the technology for producing photovoltaic power generation systems at a cost less than 1/100 of those by current technology. In fiscal 1974, basic study was made on formation technology of particle non-accelerating growth Si thin film crystals. In addition, evaluation was made on formed thin film crystal characteristics, and studies were also made on junction formation for thin film crystals, and on thin film formation and junction formation for indium phosphide compound semiconductor thin films. The research includes (1) study on formation technology for particle non-accelerating growth Si thin film crystals, (2) evaluation on Si thin film crystals, (3) study on junction formation technology for Si thin film crystals, and (4) study on indium phosphide compound semiconductors. Evaluations were made on thin film formation technology by CVD, and on crystallographical and electrical characteristics of the formed thin films. The evaluation results clarified the compatibility between substrates and Si thin films, the formation condition of columnar structure films, and the effect of growth conditions on a carrier density or mobility. (NEDO)
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Energy Technology Data Exchange (ETDEWEB)
Tatsuta, M [New Energy and Industrial Technology Development Organization, Tokyo (Japan)
1994-12-01
This paper reports the study results on the fabrication technology of CuInSe2 based PV cell in fiscal 1994. (1) On formation of high-quality CIGS thin films by bilayer method, Mo film was deposited on a glass substrate by sputtering, and CIGS film with different Ga/In ratios was next formed on the substrate by quaternary simultaneous deposition at different In and Ga deposition speeds. In addition, CdS film was deposited on the CIGS film, and ZnO and ITO films were finally deposited on it by sputtering to complete solar cell. This solar cell offered the maximum conversion efficiency among cells using CIGS film. (2) On formation of high-quality CIGS thin films by three-stage method, a certain correlation was found between substrate temperature and CIGS film composition by monitoring substrate temperature in film forming process. This phenomenon allowed rigorous control of CIS film compositions important for CIS thin film solar cells. (3) On low-cost process technology for thin film formation, Cu(In,Ga)S2 solid solution film was fabricated by expanded selenic process. 3 figs.
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Energy Technology Data Exchange (ETDEWEB)
NONE
1978-03-01
As part of the research and development project for producing photovoltaic power generation systems at reduced cost, the R and D efforts are made for producing particle nonacceleration growth type silicon thin-film crystals. The research items are (1) research on thin-film crystals, and (2) research on cell-structuring method. The item (1) studies quantities, types and electrical properties of impurities and crystal defects in the polycrystalline ingots, produced by the Czochralski method from metal grade silicon and purified metal grade silicon stocks. Next, the substrate prepared above is coated with a thin film of silicon by the vapor-phase growth method with dichlorosilane as the source, to evaluate the thin-film crystals by measuring the crystal defects and lifetime of small numbers of carriers. The item (2) studies the effects of the solder dipping method. In addition, unevenness of photoelectric current is analyzed by a laser scanning microscope, to investigate the effects of the secondary impurities and crystal defects in the substrate crystals on photoelectric current. As a result, it is found that conversion efficiency is improved by grading the hole concentration in the p-type activated layer. The targets of 10 to 20 m{sup 2} as the area and 7 to 8% as the conversion efficiency are attained by preparing the crystals again. (NEDO)
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Energy Technology Data Exchange (ETDEWEB)
NONE
1998-03-01
Complex beam epitaxy (CxBE) process was proposed and demonstrated as new deposition process of multi-element oxide thin films. This process radiates excimer laser onto a metal complex target of ethylenediamine-tetraacetate complex under reduced pressure oxygen atmosphere condition in a reaction vessel to supply raw material onto a heated substrate. This process allowed deposition of YBCO123 phase hetero-epitaxial film onto a single-crystalline SrTiO3 substrate. This process was proved to be promising through study on crystal orientation, composition transcription and surface smoothness of the obtained oxide thin films. In addition, epitaxial ZnO film was also deposited onto a single crystalline Al2O3 substrate by this process. The relation between the obtained film and substrate epitaxy was examined, and photoluminescence of specimens was measured by triple wave of Nd:YAG laser. As a result, it was clarified that the epitaxial ZnO film prepared by this process is useful as laser material. 60 refs., 48 figs., 5 tabs.
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Energy Technology Data Exchange (ETDEWEB)
NONE
1980-03-01
The R and D was intended to establish the manufacturing technology of a particle non-accelerated growth type silicon thin film crystal, for the purpose of developing a technology for enabling the production of a solar power generation system, whose price is practically 1/100 compared with that of building the system with the current technology, and the R and D was also intended to build the system using such silicon material. While a simple purification method was examined for a low purity metallurgical-grade silicon, a solar-grade silicon (SOG) was developed as the new material this year, with a solar cell experimentally manufactured having a structure directly joined to the substrate material and with evaluation carried out on the characteristic of such solar cell. The application of 'gettering' was tried which was for removing harmful impurities from the substrate obtained from such material, bringing an outlook of manufacturing a solar cell with a conversion efficiency of 10%. Concerning the SOG-Si, the efficiency of 13% or higher was attained through the improvement of the manufacturing process. This was the value comparable to the case of using a conventional high purity monocrystal wafer. Further, the application of an ion implantation method was studied for the purpose of getting a low cost. (NEDO)
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Energy Technology Data Exchange (ETDEWEB)
NONE
1997-03-01
A study was made on factors of the formation of high-quality thin films in the pulse laser deposition (PLD) method, a synthesis method of high-grade functional material thin films. In the experiment, plume current measurements using Cu target were conducted for the control of electric and magnetic fields. Especially, the measuring evaluation was made of the two-dimensional distribution including not only the central part of the substrate placed opposite to the target, but the periphery of the substrate. As a result, the following was found out. The distribution of charged particles in the plume is different in positive charge and negative charge, and the negative charge is dispersed/distributed more widely. Accelerating/decelerating effects of charged particles by the electric field are saturated when the bias voltage absolute value is approximately 100V. Ionization is promoted by giving the magnetic field, and the plume distribution is expanded. Positive charged particles of the plume in the magnetic field are decelerated. In the distribution control by giving the electric field, it is effective to think improvement of the distribution not by attracting charged particles by the electric field, but by shutting out charged particles of the same polarity. 29 refs., 75 figs., 2 tabs.
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Energy Technology Data Exchange (ETDEWEB)
Tatsuta, M [New Energy and Industrial Technology Development Organization, Tokyo (Japan)
1994-12-01
This paper reports the study results on technological development for qualitative improvement of a-Si solar cells after initial degradation in fiscal 1994. On the fabrication technology of light-stable a-Si films, the film formation method possible to control combined hydrogen by repetitive formation/treatment was developed. The obtained high-quality light-stable a-Si film was featured by low defect density in a wide optical band gap range, and defect density of nearly 3 {times} 10{sup 16}/cm{sup -3} after light irradiation. The light degradation rate of the cell where the a-Si film was applied to i layer was relatively stable by 10% or less. The a-Si/a-Si double-layer tandem cell fabricated by this technology produced a high conversion efficiency of 10.5%. By applying {mu}c-Si material to photoactive layer as narrow band gap material, the cell with optical sensitivity even in long wavelength ranges more than 1000nm was obtained. The a-Si/{mu}c-Si double-layer tandem cell produced an initial efficiency of 8.0% and an efficiency after degradation of 7.5%. 12 figs., 3 tabs.
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Energy Technology Data Exchange (ETDEWEB)
NONE
2000-03-01
The R and D project has been implemented for developing the thin film-making process techniques which can increase areas of titanium oxide (TiO{sub 2}) photocatalysts sensitive to visible light and their mass production. The fundamental investigations are directed to elucidation of the mechanisms involved in manifestation of activity in visible light of the visible light-sensitive thin film doped with the Cr, V or other ions. The sputtering involving no ion implantation is devised for producing the thin films, to realize the highest visible light sensitivity recorded for the thin TiO{sub 2} film. The sputtering process is investigated in detail for the film-making conditions, e.g., Ar pressure, effects of coexisting O{sub 2} gas, and power gap. The conditions under which the thin film serviceable under commercial conditions can be produced are not established yet, but it is confirmed that the coating film shows superhydrophilicity and photocatalytic activity for, e.g., sterilization, when irradiated with ultraviolet ray. The method has been established for evaluating deodorizing and contamination-preventive functions of the thin films in ultraviolet and visible rays. The project has also confirmed applicability of the techniques to the commercial products, and established the self-cleanable catalyst by combining the oxide catalytic function with the photocatalytic function. (NEDO)
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Energy Technology Data Exchange (ETDEWEB)
NONE
2001-03-01
The thin film structure of photocatalytic titanium oxide, capable of efficiently decomposing hazardous pollutants or the like, is refined to have a nanometric scale structure for a larger specific surface for the development of a photocatalytic thin film or powder film and for the development of decomposition capable air cleaner using a thus developed photocatalytic film. Described in this report are the results of a study conducted to elucidate the fabrication conditions, nanostructures, and photocatalytic features of titanium oxide thin films formed by spray thermolysis, RF (radio frequency) sputtering, reactive sputtering, and sol-gel process, a study of hazardous pollutant decomposing capability and nanostructure, the establishment of fabrication technologies, and the construction of a prototype air cleaner with the results of the said studies applied thereto. Among the various fabrication methods, the technology involving a hypersensitive thin film photocatalyst was established by combining the reactive sputtering method and the sol-gel method. It was found that the formation of prismatic crystals in the sol-gel method was the most important in achieving high performance in the hypersensitive thin film photocatalyst. (NEDO)
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Energy Technology Data Exchange (ETDEWEB)
Tatsuta, M [New Energy and Industrial Technology Development Organization, Tokyo (Japan)
1994-12-01
This paper reports the study results on the fabrication technology of amorphous Si solar cell modules in fiscal 1994. (1) On process technology for prototype film substrate solar cells, an advanced preprocessing equipment for film substrates, stepping roll type film forming technology, and prototype submodules were studied. A conversion efficiency of 7.2% was achieved by use of the submodule formed in an effective region of 40 {times} 40cm{sup 2}. (2) On efficiency improvement technology for film substrate solar cells, p/i and n/i interfaces, forming condition for Ag film electrodes, film thickness of transparent electrode ITO, and optimum transmissivity were studied. (3) On technology for advanced solar cells, high-quality a-SiGe: H film, ion control in plasma CVD, and a-Si film formation by plasma CVD using SiH2Cl2 were studied as production technology of narrow gap materials. (4) On advanced two-layer tandem solar cells, the defect density in optical degradation of a-Si cells by reverse bias dark current was evaluated, and outdoor exposure data were analyzed. 4 figs., 1 tab.
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Energy Technology Data Exchange (ETDEWEB)
Tatsuta, M [New Energy and Industrial Technology Development Organization, Tokyo (Japan)
1994-12-01
This paper reports the study results on the fabrication technology of CdS/CdTe solar cell modules in fiscal 1994. (1) On the fabrication technology for high-efficiency large-area solar cells, high-quality CdTe active layer was studied. S content taken in the active layer at sintering of CdTe decreased with an increase in formed CdTe, resulting in improvement of Voc of cells. (2) On the window layer with wide band gap, the solar cell superior in collection efficiency and photoelectric characteristics could be obtained using the newly developed mixed crystal film of Cd(1-x)Zn(x)S. (3) On the forming technology of large-area coating/sintering films, improvement of CdS film quality was studied by pressurized processing of printed CdS films. As a result, improvement of film density and light transmissivity was confirmed. (4) On the leveling process technology of CdTe films, smooth surface films were obtained by experiment using an equipment simultaneously exciting samples in all directions as one of uniform coating methods of films. 7 figs.
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Energy Technology Data Exchange (ETDEWEB)
NONE
1999-03-01
A new thin film manufacturing method is established to add a function to glass material surface, as a new material technology which harmonizes with global environment, and is suitable for resource re-utilization and energy conservation. It is intended to develop a leading technology to promote recycling of colored glasses by applying this technical method to colored glasses. Fiscal 1998 has implemented subsequently to fiscal 1997 the following subjects in the three research items composed of a new manufacturing method of functional thin films, application of the functional thin films to colored glasses, and the comprehensive investigative studies: establishment of an industrial manufacturing method for color coating liquid and evaluation of basic characteristics of the colored functional thin films, optimization of element technology for photo-sensitive gel films by means of chemically modifying metallic alkoxide, tests of forming films on glass bottles and plate glasses by using a coating machine installed in fiscal 1997, design and prototype fabrication of a new demonstration coating machine, and analysis on thermal decomposition of the colored thin films. Optimization was performed on the element technology for manufacturing sol-gel functional thin films, and a survey was carried out on recycling systems of colored glasses adopted in Europe. (NEDO)
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Energy Technology Data Exchange (ETDEWEB)
Oyagi, H; Okada, Y; Yamaguchi, H; Shiota, T; Kuroda, S; Igarashi, O; Tanino, H; Makita, Y; Yamada, A; Kimura, S; Ohara, A; Niki, S; Shibata, H; Fons, P [Electrotechnical Laboratory, Tsukuba (Japan)
1994-12-01
Described herein are the results of the FY1994 research program for analysis and evaluation for thin-film compound semiconductor solar cells. The study on epitaxial growth and optical properties of the thin films of CuInSe2 and CuGaSe2 evaluates the thin epitaxial films grown under various conditions, showing morphology of the defects at the interface of heteroepitaxial growth. These results are used to set the growth conditions under which a thin film of high luminescence by exciter recombination is produced. The study also gives information of luminescence transition in the vicinity of the band ends and of energy level between the bands. The study on structural analysis of the epitaxially grown thin films of CuInSe2 investigates dependence of lattice constants of the MBE-grown CIS layer on film thickness by the X-ray diffractometry based on the bond method. The study on epitaxial growth by the Se(CH3)2-halogen transfer method tests epitaxial growth of the single-crystalline Mo on a substrate of single-crystalline sapphire. 5 figs.
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Energy Technology Data Exchange (ETDEWEB)
NONE
1998-03-01
It is intended to identify and analyze quickly and accurately the technological trends inside and outside the country on thin film solar cells, to reflect the results effectively on research and development of practical application of the thin film solar cells for power use, and to aid the research on practical application of the technology to manufacture the thin film solar cells. This fiscal year introduced the new project of researching and developing the poly-crystal silicon-based thin film solar cells. Discussions were given on designing the solar cells, including setting of thickness of an active layer required to improve efficiency of the silicon-based thin film solar cells, the light confining technology, and surface passivation. Comparisons and discussions were given on the new amorphous/poly-crystal silicon thin film manufacturing method and the conventional plasma CVD process. A research development program was introduced for a super laboratory to aid establishing the practical application technology for the silicon-based thin film solar cells. Chalcopyrite compounds including CuInSe2, and CdTe have not shown deterioration even in a long-term outdoor exposure test, hence they are noted as materials for high-efficiency solar cells and studied actively. Although still small in area, the net conversion efficiency was found in the order of 17%. Technological development has started to search mass production processes and commercialization possibility in the future. (NEDO)
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Energy Technology Data Exchange (ETDEWEB)
Tatsuta, M [New Energy and Industrial Technology Development Organization, Tokyo (Japan)
1994-12-01
This paper reports the study results on the fabrication technology of over-layered TCO on tempered glass in fiscal 1994. (1) On the fabrication technology of heat-resistant over-layered TCO, thermal deformation of TCO substrates was studied by both experiment and numerical computation. The thermal deformation increased with carrier concentration. As the observation result on change in lattice strain of heated TCO films by high-temperature X-ray diffraction, lattice strain was largely affected by thermal expansion. (2) On development of the low-temperature heat treatment method of TCO films, a technological prospect was obtained for fabrication of low-resistance TCO films by heat treatment without strength deterioration of tempered TCO substrates. (3) On development of cost reduction technology, the large-area CVD equipment was devised on the basis of the inline tempering method which tempers substrate glass by air cooling after formation of SnO2 film as fabrication method of tempered TCO. The TCO substrate tempered by air cooling could endure the drop test of 227g and 1.5m. 5 figs., 1 tab.
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Energy Technology Data Exchange (ETDEWEB)
NONE
2000-03-01
With an objective to manufacture low-cost large-area solar cell modules, developmental research has been performed on a film manufacturing technology using the dessolution deposition process. This paper summarizes the achievements in fiscal 1999. The research has been performed on a technology to form a thin silicon film directly on carbon substrates being substrates of different kinds, without using seed crystals. The researches made up to the previous fiscal year has made possible to form the film onto a substrate of about 5-cm square, has fabricated cells although with a small area, and indicated the importance of reducing concentrations of impurities in the solvent metals used. The researches performed during the current fiscal year executed modifications to reduce the temperature distribution in the substrate surfaces, including size increase in the heater, and improvement in the cooling heat conduction mechanism. As a result, films were formed successfully on 7.5-cm square substrates. In reducing the process temperatures, it was made clear that films can be formed at lower than 700 degrees C by using zinc as a solvent metal. Furthermore, the purity enhancement in the solvent metal achieved a conversion efficiency of 11.6% although the area is as small as 3.73 cm{sup 2}. (NEDO)
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Energy Technology Data Exchange (ETDEWEB)
NONE
2000-03-01
A thin film is developed which adds new functions to the surface of glass materials. The method is applied to the coloring of glass for the enhancement of recyclability (for example, by coating colorless glass bottles with colorful thin film) and to the functionalization of glass. Studies are conducted about the assessment of coloring-capable thin film basic characteristics, manufacture of liquids for application, and the manufacture of photosensitive gel thin film using chemically modified metal alkoxides. It is found that use of functional pigments reduces the transmissivity of ultraviolet and infrared rays. A method for manufacturing coloring liquids for application to glass bottles and a method of improving film durability using a 3,2-functional silane are established. Ultrafine gold/cuprous oxide powder, azobenzen based pigments, etc., are deposited on porous glass for the formation of a photoresponsive film. Conditions for color application to round glass bottles are optimized by use of an air spray device. Film exfoliation during colored glass bottle transportation is lessoned to a practically acceptable level by modifying the carton pack configuration. A large roll-type applicator is operated to successfully form a homogenous coating on a 1.8m times 1m glass plate. Double glazing capable of light modulation is also manufactured. (NEDO)
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Energy Technology Data Exchange (ETDEWEB)
NONE
1999-03-01
The aim is to manufacture the above at low cost by a dissolution/deposition method. Under this method, a film is fabricated containing crystals high in quality and large in size though the film area is very small. In fiscal 1998, an effort to fabricate a film to cover a 10cm square substrate failed. The failure is explained by that the heater was too small for the substrate area and that the failure to uniformly heat the substrate resulted in an inplane temperature distribution greater than expected. The furnace was modified in a minor way to narrow substrate temperature distribution as much as possible. Another attempt was made to fabricate a larger-area film on a 5cm square substrate, and then crystals grew to cover approximately the whole surface of the 5cm square substrate. Efforts will continue to achieve the goal. As for the mechanism of film fabrication on substrates of different kinds, self-coating is now described by difference in heat conductivity between a carbon substrate and silicon substrate. Thanks to individual control in a small film fabricating unit, a film thickness of approximately 100 micrometers was achieved. The distance of diffusion was 30 micrometers or more in the case of a small area, and the efficiency of a solar cell using this film was found at 10.2%. (NEDO)
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Energy Technology Data Exchange (ETDEWEB)
NONE
1998-03-01
Research and development was performed by noticing on the plasma spraying method as a process that can manufacture thin poly-crystalline silicon films at a high speed. Fiscal 1997 has established a technology that can form a silicon film directly without using seed crystals in an area of 2-cm square on a carbon supported substrate by using a small film manufacturing equipment using the dissolution and deposition process. The size of the crystal is as very large as several hundred {mu}m, by which a possibility of making high-performance solar cells was verified. Discussions were given to apply this technology to large-area substrates, whereas a device was developed, which is capable of forming a film in an area corresponding to 10-cm square. According to a film forming experiment using this device, the film has begun being formed on part of a 10-cm square substrate, verifying the effectiveness of this method. While the film thickness is about 100 {mu}m, it was confirmed that the crystal size will not change even if the thickness is made mechanically as thin as about 50 {mu}m. Further discussions were given on enhancement of wettability by means of coating, and light enclosing structure. (NEDO)
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Energy Technology Data Exchange (ETDEWEB)
Matsuda, A; Oeda, H; Yamasaki, S; Hata, N; Kondo, M; Toshima, Y; Sakata, I; Ganguly, G; Suzuki, A; Kamei, T; Okushi, H; Nonaka, H; Oda, N; Katagiri, H; Ichimura, N; Kokubu, K; Nakamura, K; Sekikawa, T; Yamanaka, M [Electrotechnical Laboratory, Tsukuba (Japan)
1994-12-01
Described herein are the results of the FY1994 research program for analysis and evaluation for thin film solar cells. The study on quantitative analysis of hydrogen atoms in a plasma determines quantity of hydrogen atoms in the plasma of monosilane diluted with hydrogen. It is found, contrary to expectation, that quantity of hydrogen atoms in the plasma decreases as it is more diluted with hydrogen. The study on light-induced degradation of the thin chlorine-base amorphous silicon films confirms that the plasma CVD method with 20% of dichlorosilane gas added to monosilane gas produces the thin amorphous silicon film 3 times faster than the conventional method. The thin film has essentially the same defect density as the one prepared by the conventional method, showing good photoelectric characteristics. The thin film of chlorinated amorphous silicon has a 1 digit lower defect density than the conventional one of amorphous silicon, as revealed by the accelerated degradation test with irradiated laser light and the constant current method to determine saturated defect density. 3 figs.
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Energy Technology Data Exchange (ETDEWEB)
NONE
1999-03-01
A microcrystalline Si thin film is used to form the i-layer of a narrow gap a-Si based thin film solar cell. Since a microcrystalline p-layer is to act as the seeding crystal layer for the microcrystalline i-layer, it has to be very high in crystallinity and therefore is produced under high hydrogen dilution conditions. In this process, a problem arises of the darkening of the underlying transparent SnO{sub 2} electrode. Since this is due to chemical reaction on the SnO{sub 2} surface layer, blackening is prevented by shortening the film fabrication time, and then an excellently microcrystalline p-layer is obtained. Furthermore, by inserting a microcrystalline i-film buffer layer of low fabrication rate into the p/i boundary, plasma damage on the microcrystalline p-layer is inhibited for the fabrication of a microcrystalline i-layer high in crystallinity at high film fabrication rates. A high Voc is then obtained even when the microcrystalline p-layer is very thin. If the hydrogen dilution rate is too low when the i-layer film fabrication rate is high, the initially fabricated layer turns out to be thick to the detriment of film performance. On the other hand, the p-layer or the buffer layer will be etched when the hydrogen dilution rate is too high. The problem is solved by continuously varying the hydrogen dilution rate from high to low during i-layer fabrication. (NEDO)
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Energy Technology Data Exchange (ETDEWEB)
NONE
2000-03-01
The research and development project is implemented for the amorphous/microcrystalline solar cells with the thin microcrystalline silicon film as the i layer, and the FY 1999 results are reported. The fabrication technologies are investigated for the microcrystalline silicon solar cells of pin or nip structure by RF or VHF plasma CVD using SiH{sub 4} and H{sub 2} as the stock gases. The tests are conducted for evaluating characteristics of the thin microcrystalline silicon film, to investigate the effects of film-making pressure, power and hydrogen dilution rate on the characteristics at a constant film-making temperature of 180 degrees C. The researches on the fabrication technologies for the microcrystalline solar cell of pin structure confirm that use of VHF plasma CVD improves crystallinity, electrical and optical characteristics of the p-type thin microcrystalline silicon film. The researches on the fabrication technologies for the microcrystalline solar cell of nip structure covers transparent substrates, film-making speed of the p layer, power and substrates, and a conversion efficiency of 7.5% is realized by the solar cell formed on a texture substrate. (NEDO)
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Energy Technology Data Exchange (ETDEWEB)
NONE
1998-03-01
The paper described the fiscal 1997 result. Using organic pigment and dye, the basic composition of sol-gel colored coating liquid for glass bottles and sheets was selected to clarify characteristics of gel films. Moreover, chemical modification and optical sensitivity of metallic alkoxide were studied to obtain a trially produced colored glass bottle use coating liquid. As to sheet glass, strength of the gel film is low, which requires further improvement. In relation to optical sensitive gel films, the reaction of various metallic alkoxides and {beta}-diketones was discussed to clarify chemical reactivity with utltaviolet rays. Trial design was also conducted of the coating equipment. The paper examined by literature the present status of recycling systems of colored glass bottles and the technical development in European countries. The problem is a method to wash colored bottles for sterilization. To make colored films durable, it is necessary to form films by organic-inorganic hybrid thin films. Also discussed was a possibility of changing the washing method by administrative guidance. 27 refs., 62 figs., 42 tabs.
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Energy Technology Data Exchange (ETDEWEB)
NONE
2000-03-01
The research and development project is implemented for production of low-cost, large-area modules of CdTe solar cells by the high-quality film-making process and high-function patterning, and the FY 1999 results are reported. The research program for the large-area TCO film-making technologies involves investigations on improvement of SnO{sub 2} film quality by the mist method and continuous film-making, which lead to continuous, stable production of 34 substrates of low resistance of 9.7{omega} on the average. The program for production of the large-area, thin-film CdS/CdTe solar cells involves production of TCO and CdS by the mist method, and patterning of the laminated TCO/CdS film by laser scribing. The CdTe film is formed by the atmospheric pressure CSS method, and treated with CdCl{sub 2} to improve its crystallinity. The CdTe film is patterned by sand blasting, and provided with the carbon and silver electrodes by screen printing, to complete the cell. The process is totally effected at the atmospheric pressure, needing no vacuum device. The CdTe solar cell assembly (130 cells connected in series, opening area: 5,413cm{sup 2}), fabricated on a trial basis, achieves a conversion efficiency of 10%. (NEDO)
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Energy Technology Data Exchange (ETDEWEB)
NONE
2000-03-01
With an objective to put amorphous solar cells for power use into practical use, research and development has been performed on a low-cost mass production technology for modules with large area and less deterioration using film substrates. This paper summarizes the achievements in fiscal 1999. In developing an efficiency enhancing technology, development of an a-Si/a-SiGe/a-SiGe triple cell structure was launched, and discussions were given on band gaps, film forming conditions, and film thickness. In developing a film forming speed enhancing technology, systematic experiments were performed, as well as theoretical analysis on the film forming mechanism in the plasma CVD process. In developing the process technology for film substrate solar cells, with regard to an a-Si production device of the multi-chamber arranged stepping roll system, six plasma CVD chambers were increased to 13 chambers to improve the electrode forming speed and such processes as drilling low-cost substrates, and laser patterning. In trial fabrication of a triple cell, a module in which one row of the SCAF cell is laminated provided an initial efficiency of 9.64%. (NEDO)
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Energy Technology Data Exchange (ETDEWEB)
NONE
1998-03-01
With an objective to improve efficiency and reduce cost of CIS-based thin film solar cells, research and development has been made on technologies to increase high-quality CIS film area and technologies to increase speed in the manufacturing process. This paper describes the achievements attained during fiscal 1997. The research covered development of technologies to form high-grade Cu (In, Ga) Se{sub 2} (CIGS) film by using the multi-dimensional deposition process, component technologies for forming a rear electrode, a buffer layer and a transparent electrode, and patterning technologies. As a result of the research, thickness of the CIGS film was reduced to half as much as that of the conventional films, having achieved conversion efficiency of 13.1%, which corresponds to about 90% of the conventional CIGS solar cells. In addition, elucidation was made on the effect of an MoSe{sub 2} layer existing on interface with CIGS/Mo in a CIGS solar cell imposed on solar cell characteristics. In developing an Mo film laser scribing technology, intensity dependence of laser energy was made clear, the energy being required for scribing according to surface condition of the Mo film. (NEDO)
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Energy Technology Data Exchange (ETDEWEB)
NONE
1998-03-01
The target is a low-cost CdS/CdTe solar cell of a large area (60cm times 90cm), the establishment of mass-production technologies for the cell, and the enhancement of production efficiency. A thin film formation technology of subjecting CdS film organic metal to pyrolysis is established, which reduces photoabsorption loss in the shortwave domain of wavelength of not longer than 500nm, reduces reflection loss in the film, and improves on short-circuit current density. Improvement is also achieved on CdTe film quality and junction quality by use of a proximity sublimation method in a vacuum, when a conversion rate of 16.0% (1cm{sup 2}) is attained which is the highest in the world. Based on the results of the above-said efforts, a 3.3mm-thick glass substrate is employed for CdTe film to develop into a 30cm times 60cm-large size, with the film thereon uniformly thick over a large area thanks to a normal pressure proximity sublimation method. Studies are made toward a process nearer to the ultimate product and, using the patterning technique, a 30cm times 60cm-large CdTe solar cell is tentatively built realizing a conversion rate of 9.8%. (NEDO)
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Energy Technology Data Exchange (ETDEWEB)
NONE
2000-03-01
The project aims to enhance the stability of amorphous solar cells. For elevating TCO (transparent conductive oxide) substrate transmittance to an ultrahigh level and for obtaining amorphous layers less to suffer photodegradation, efforts were made to develop substrate materials stable upon exposure to plasma and low in defect density. In the study of TCO, a high-transmittance glass substrate was employed and TCO was made thinner, and the specimen achieved transmittance of 91.3% or 6.3% over that of the conventional type. In the study of low reflection films, it was found that their transmittance came to be stable and remain so after 150 days after a weatherproof test. In the study for stability enhancement, optimization was carried out for a plasma resisting Ga{sub 2}O{sub 3}-added ZnO film for the manufacture of a substrate material capable of properly behaving in a high-speed a-Si film fabrication process. Low-temperature film fabrication was studied to enable low-cost manufacturing, and it was learned that a 4 times 10{sup -4} ohm/cm low-resistance film was obtained by sputtering Ga{sub 2}O{sub 3}-added ZnO where magnetism was intensive at room temperature, that films excellent in crystallinity were obtained by the same method even at low temperatures, and so forth. (NEDO)
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Energy Technology Data Exchange (ETDEWEB)
NONE
1999-03-01
The project intends to improve on large-area amorphous silicon solar cell performance and to develop high-throughput manufacturing technologies for a reduction in the cost of modules. A film substrate type amorphous solar cell structure of the serial connection type named SCAF (series-connection through apertures formed on film) is contrived. Under this method, film formation using a stepping roll system newly developed for glass substrates may be applied, and the number of manhours required is allowed to be less than under conventional serial connection forming processes. The new technique is characterized in that serial connections are established via through-holes provided in plastic substrates. Making use of the technology, progress is attained in the development of high-throughput process technology for film substrate type amorphous solar cells and of efficiency enhancement technology. In fiscal 1997, an electron beam unit for plasma generation aiming at the elucidation of reaction processes in plasma was introduced, and technologies based on the equilibrium discharge technique were developed enabling high-speed a-Si film formation without degradation in film quality. The effect of trace boron addition to the tandem cell bottom I layer was investigated, and a stabilization rate of 8.05% was achieved using a 40cm times 80cm large SCAF cell. In fiscal 1998, endeavors were exerted for similar developments. (NEDO)
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Energy Technology Data Exchange (ETDEWEB)
NONE
1999-03-01
Cost reduction for the above-named solar cells is the aim of this effort. On the basis of the results of past studies, a technology is established of fabricating a thin CdS film by subjecting a CdS film to organometal pyrolysis, and this brings about a decrease in photoabsorption loss in the range of waves shorter than 500nm and a decrease in in-film reflection loss for an increase in short-circuit current density. A proximity sublimation method is used for CdTe film fabrication, which improves on film quality and film adhesion. These efforts result in the achievement of a conversion efficiency of 16.0% which is the highest in the world. Studies are promoted in a process nearer to the ultimate form, and a 30cm times 60cm large CdTe solar cell is fabricated on the basis of a patterning technique, and the product attains a conversion efficiency of 9.8%. In fiscal 1998, studies center about the establishment of a film fabrication process for a medium-are substrate and about the enhancement of its conversion efficiency, and facilities capable of dealing with large-area substrates are introduced and operated. In a typical achievement, a CdTe solar cell is experimentally fabricated in a process which is wholly under normal pressure, and the product with an aperture area of 1376cm{sup 2} exhibits a conversion efficiency of 10.5% according to JQA (Japan Quality Assurance Organization). (NEDO)
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Energy Technology Data Exchange (ETDEWEB)
NONE
1997-03-01
Described herein are the FY 1996 results of development of fabrication technologies for high-quality CuInSe{sub 2}-based photovoltaic cells. The Cu-Ga alloy/In-stacked precursor film is prepared for production of the high-quality thin-film absorber applicable to large-area module fabrication, and selenized by the vapor-phase selenization in a H{sub 2}Se gas atmosphere to produce the thin light-absorbing film in which In and Ga are present at graded concentrations. Increasing Ga alloy content in the CIGS-based thin-film photovoltaic cell fails to widen the forbidden band and improve V{sub oc}, and further optimization works are needed. The method is developed for production of thin-film buffer layer of sulfur-containing Zn compound which can give the cell characteristics equivalent to those of CdS generally used for CIS-based thin-film photovoltaic cell. It is clarified that the photovoltaic cell characteristics can be improved by use of a transparent electroconductive ZnO film of stacked structure, produced by a combination of RF sputtering and DC sputtering. For the patterning technologies necessary for forming series connection on a mini-module, the laser scribing method is applicable to the metal base-electrode, and the mechanical scribing method to the light absorber and window layer. (NEDO)
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Energy Technology Data Exchange (ETDEWEB)
NONE
1998-03-01
These technological developments are intended to develop technologies to manufacture with improved quality the silicon-based thin film solar cells. In order to analyze manufacturing conditions for micro crystal silicon thin films as the narrow-gap amorphous silicon-based films, films were manufactured in the vicinity of borders of amorphous/micro crystal silicon film manufacturing conditions. The present film manufacturing did not present effects of suppressing deterioration of hydrogen diluted light. In order to elucidate the light deterioration mechanism in hydrogenated amorphous silicon films and study the suppression thereof, discussions were given on impurities in the film, including oxygen. By using an ultra high vacuum plasma CVD having a thoroughgoing baking system, an oil-free exhaust mechanism, and a raw material gas refining mechanism, impurities were added to and removed from a reaction vessel, and an ultra-high purity Si:H film was manufactured, which has been removed of impurities from the raw material gas, resulting in reduction of O, C and N standing no comparison. According to the result of a light irradiation experiment on an ultra-high purity film obtained under an accelerated deteriorating condition by using a pulse laser, the model assuming the light induced defect and the pair of impure atoms has been denied. (NEDO)
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Energy Technology Data Exchange (ETDEWEB)
NONE
2000-03-01
With an objective to assist research and development to put thin film solar cells for power use into practical use and a research to put thin film solar cell manufacturing technologies into practical use, survey and research have been performed on trends in the technologies inside and outside the country. Characteristic points in thin film solar cells during the current fiscal year include: expansion of production scale of amorphous silicon solar cells, rapid progress in poly-crystalline silicon thin film solar cell technologies, and enhancement of performance in large-area modules in the a-Si, CIGS, and CdTe systems. In the trends in research and development of amorphous systems, expectation is heightening on elucidation of optical deterioration phenomena, and establishment of suppression technologies thereof. Although the highest efficiency was not renewed in thin film solar cells of small areas, progress was seen in the post-stabilization efficiency in large-area modules. A thin film solar cell manufacturing plant having an annual production capacity of 20 MW was put into operation in October in Japan. Micro (poly) crystalline silicon based solar cells have high possibility of being compatible in cost reduction and performance improvement, and energetic researches are being carried out on them in recent years as the most promising candidate of the next generation solar cells. (NEDO)
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Energy Technology Data Exchange (ETDEWEB)
NONE
1998-03-01
As a plan to develop technologies to manufacture materials and substrates for thin film solar cells, it is intended to reduce defect density, enhance film forming speed, largely improve the photo-electric conversion efficiency and increase manufacturing productivity. These goals will be realized by establishing methods to control defect density, crystal particle diameters and crystallization rate in silicon crystal systems. A technology to form micro-crystal silicon-based thin films will be developed, that have superior photo-stability, and are capable of realizing low cost and mass production. Discussions will be given on a high-density plasma control technology, a fundamental property evaluation technology for micro crystal silicon thin films, and a device design simulation technology. A technology will be developed to form amorphous silicon layer on a stainless steel substrate by using the plasma CVD process. At the same time, discussions will be given on optical annealing and thermal annealing as reformation methods. Fiscal 1997 has surveyed component technologies to identify and analyze quickly and accurately the technical trends inside and outside the country, and to mass produce thin film solar cells. The Material and Substrate System Technology Subcommittee (silicon crystals) was held to deliberate the four-year development program and its progress. (NEDO)
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Energy Technology Data Exchange (ETDEWEB)
NONE
1998-03-01
Development will be made on high-performance a-solar cells as part of developing practical application technology for a-solar cells for electric power use. Development will be also made on a low-cost process technology. This paper describes the achievements attained during fiscal 1997. Quality improvement has been realized by using a high RF power hydrogen dilution process on a-Si films for front cells of lamination type cells. Four times faster film forming speed was obtained even by using the VHF plasma CVD process, with film quality equivalent to those made by using the conventional RF process maintained. By optimizing the light enclosing construction, the short circuit current was enhanced by over 20%. Discussions were given on forming homogenous a-Si films by optimizing the conditions for forming films on large-area substrates, which resulted in forming film of 30 cm times 40 cm size with good homogeneity at a film forming speed three times faster than the conventional speed. A surface electrode was formed successfully with good uniformity on a substrate with a size of 60 cm times 90 cm. Productivity greater by over three times the conventional productivity was achieved in patterning of transparent electrodes by using high-output laser. Simultaneous and collective patterning and very small and long size collective patterning were realized in a-Si film selection patterning by using the plasma CVD process. (NEDO)
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Energy Technology Data Exchange (ETDEWEB)
NONE
1998-03-01
It is intended to develop thin film solar cells capable of mass production with high photo-stability and at low cost. Thus, the objective of the present research is to analyze the growth process of micro crystal silicon based thin films, the crystal being a high quality silicon crystal based material, and develop technology to manufacture high-quality micro crystal silicon thin films based on the findings therefrom. It was found that, when silicon source is available in cathode, pure hydrogen plasma forms micro crystal silicon films by using the plasma as a result of the chemical transportation effect from the silicon source. It was revealed that the crystal formation due to hydrogen plasma exposure is performed substantially by the crystals forming the films due to the chemical transportation effect, rather than crystallization in the vicinity of the surface. The crystal formation under this experiment was concluded that the formation takes place during film growth accompanied by diffusion of film forming precursors on the surface on which the film grows. According to the result obtained so far, the most important issue in the future is particularly the control of crystal growing azimuth by reducing the initially formed amorphous layer by controlling the stress in the initial phase for film formation, and by controlling the film forming precursors. (NEDO)