The Experts below are selected from a list of 76764 Experts worldwide ranked by ideXlab platform
Thomas Kieliba - One of the best experts on this subject based on the ideXlab platform.
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zone melting recrystallization of Silicon Films for crystalline Silicon thin film solar cells
Solar Energy Materials and Solar Cells, 2001Co-Authors: Stefan Reber, Walter Zimmermann, Thomas KielibaAbstract:Coarse-grained Silicon Films for crystalline Silicon thin-film solar cells have been prepared by zone melting recrystallization. A zone melting heater was modified to obtain better temperature homogeneity of the sample and higher reproducibility of the melt process. Various substrate materials of different purity and surface roughness have been tested concerning their suitability for, Silicon deposition, zone melting and solar cell process. Solar cell efficiencies up to 10.5% could be achieved on Silicon sheets from powder, capped by an intermediate layer. Silicon Films on SiAlON ceramics were successfully processed to solar cells by a completely dry solar cell process.
Tatsuya Shimoda - One of the best experts on this subject based on the ideXlab platform.
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fabrication of solution processed hydrogenated amorphous Silicon single junction solar cells
Applied Physics Letters, 2012Co-Authors: Takashi Masuda, Yasuo Matsuki, Naoya Sotani, Hiroki Hamada, Tatsuya ShimodaAbstract:Hydrogenated amorphous Silicon solar cells were fabricated using solution-based processes. All Silicon layers of the p-i-n junction were stacked by a spin-cast method using doped and non-doped polydihydrosilane solutions. Further, a hydrogen-radical treatment under vacuum conditions was employed to reduce spin density in the Silicon Films. Following this treatment, the electric properties of the Silicon Films were improved, and the power conversion efficiency of the solar cells was also increased from 0.01% to 0.30%–0.51% under the AM-1.5G (100 mW/cm2) illumination conditions.
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spin on n type Silicon Films using phosphorous doped polysilanes
Japanese Journal of Applied Physics, 2007Co-Authors: Hideki Tanaka, Haruo Iwasawa, Daohai Wang, Naoyuki Toyoda, Takashi Aoki, Ichio Yudasaka, Yasuo Matsuki, Tatsuya Shimoda, Masahiro FurusawaAbstract:We have developed a liquid precursor that can be used in a solution process to form n-type doped Silicon Films. This precursor is based on phosphorus-doped hydrogenated polysilane synthesized by photo-copolymerizing cyclopentasilane and white phosphorus. By spin-coating this precursor, we have prepared n-type amorphous Silicon Films and polycrystalline Silicon Films with resistivities of 6.5–27 Ωcm and 2.0–10 mΩcm, respectively.
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solution processed Silicon Films and transistors
Nature, 2006Co-Authors: Tatsuya Shimoda, Hideki Tanaka, Haruo Iwasawa, Daohai Wang, Takashi Aoki, Ichio Yudasaka, Yasuo Matsuki, Masahiro Furusawa, Masami Miyasaka, Yasumasa TakeuchiAbstract:The manufacture of Silicon semiconductor devices involves complicated photolithography and expensive machinery, so many researchers are seeking alternative semiconductor materials that can be handled by simple processes such as spin-coating or printing. Organic semiconductors are the most promising candidates but they still lack performance and reliability. Shimoda et al. have taken a different approach, printing a Silicon transistor itself, not a substitute. They successfully fabricated polycrystalline Silicon transistors by spin-coating a novel liquid precursor. This solution-based approach can also be adapted for ‘ink-jet’ printing of transistors. The development of a process whereby Silicon can be prepared from a liquid allows the printing of semiconductor devices directly from solution. The use of solution processes—as opposed to conventional vacuum processes and vapour-phase deposition—for the fabrication of electronic devices has received considerable attention for a wide range of applications1,2,3,4,5,6,7, with a view to reducing processing costs. In particular, the ability to print semiconductor devices using liquid-phase materials could prove essential for some envisaged applications, such as large-area flexible displays. Recent research in this area has largely been focused on organic semiconductors8,9,10,11, some of which have mobilities comparable to that of amorphous Silicon11 (a-Si); but issues of reliability remain. Solution processing of metal chalcogenide semiconductors to fabricate stable and high-performance transistors has also been reported12,13. This class of materials is being explored as a possible substitute for Silicon, given the complex and expensive manufacturing processes required to fabricate devices from the latter. However, if high-quality Silicon Films could be prepared by a solution process, this situation might change drastically. Here we demonstrate the solution processing of Silicon thin-film transistors (TFTs) using a silane-based liquid precursor. Using this precursor, we have prepared polycrystalline Silicon (poly-Si) Films by both spin-coating and ink-jet printing, from which we fabricate TFTs with mobilities of 108 cm2 V-1 s-1 and 6.5 cm2 V-1 s-1, respectively. Although the processing conditions have yet to be optimized, these mobilities are already greater than those that have been achieved in solution-processed organic TFTs, and they exceed those of a-Si TFTs (≤ 1 cm2 V-1 s-1).
Kenneth E Goodson - One of the best experts on this subject based on the ideXlab platform.
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thermal conduction in doped single crystal Silicon Films
Journal of Applied Physics, 2002Co-Authors: Mehdi Asheghi, Katsuo Kurabayashi, Reza Kasnavi, Kenneth E GoodsonAbstract:This work measures the thermal conductivities along free-standing Silicon layers doped with boron and phosphorus at concentrations ranging from 1×1017 to 3×1019 cm−3 at temperatures between 15 and 300 K. The impurity concentrations are measured using secondary ion mass spectroscopy (SIMS) and the thermal conductivity data are interpreted using phonon transport theory accounting for scattering on impurities, free electrons, and the layer boundaries. Phonon-boundary scattering in the 3-μm-thick layers reduces the thermal conductivity of the layers at low temperatures regardless of the level of impurity concentration. The present data suggest that unintentional impurities may have strongly reduced the conductivities reported previously for bulk samples, for which impurity concentrations were determined from the electrical resistivity rather than from SIMS data. This work illustrates the combined effects of phonon interactions with impurities, free electrons, and material interfaces, which can be particularly...
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phonon scattering in Silicon Films with thickness of order 100 nm
Applied Physics Letters, 1999Co-Authors: Kenneth E GoodsonAbstract:Although progress has been made in the ab initio simulation of lattice dynamics in semiconducting crystals, information about the relaxation of nonequilibrium lattice vibrations remains incomplete. This work studies the relaxation times of room-temperature thermal phonons through measurements of thermal conduction along monocrystalline Silicon Films of thickness down to 74 nm. A repetitive oxidation and etching process ensures that the purity and crystalline quality of the Films are comparable with those of bulk samples. Phonon-interface scattering reduces the thermal conductivity by up to 50% at room temperature. The data indicate that the effective mean-free path of the dominant phonons at room temperature is close to 300 nm and thus much longer than the value of 43 nm predicted when phonon dispersion is neglected. This study indicates that a broad variety of lattice transport characteristics for bulk Silicon can be obtained through measurements on carefully prepared Silicon nanostructures. The present data are also valuable for the thermal simulation of Silicon-on-insulator (SOI) transistors.
Mauritius C M Van De Sanden - One of the best experts on this subject based on the ideXlab platform.
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on the effect of the amorphous Silicon microstructure on the grain size of solid phase crystallized polycrystalline Silicon
Advanced Energy Materials, 2011Co-Authors: K Sharma, Annalisa Branca, A Illiberi, F D Tichelaar, M Creatore, Mauritius C M Van De SandenAbstract:In this paper the effect of the microstructure of remote plasma-deposited amorphous Silicon Films on the grain size development in polycrystalline Silicon upon solid-phase crystallization is reported. The hydrogenated amorphous Silicon Films are deposited at different microstructure parameter values R* (which represents the distribution of SiHx bonds in amorphous Silicon), at constant hydrogen content. Amorphous Silicon Films undergo a phase transformation during solid-phase crystallization and the process results in fully (poly-)crystallized Films. An increase in amorphous film structural disorder (i.e., an increase in R*), leads to the development of larger grain sizes (in the range of 700-1100 nm). When the microstructure parameter is reduced, the grain size ranges between 100 and 450 nm. These results point to the microstructure parameter having a key role in controlling the grain size of the polycrystalline Silicon Films and thus the performance of polycrystalline Silicon solar cells.
Morito Matsuoka - One of the best experts on this subject based on the ideXlab platform.
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electroluminescence of erbium doped Silicon Films as grown by ion beam epitaxy
Applied Physics Letters, 1997Co-Authors: Morito Matsuoka, Shunichi TohnoAbstract:Sharp and well-split electroluminescence has been achieved from light-emitting diodes (LEDs) fabricated from as-grown erbium–oxygen codoped Silicon Films, where all elements were in situ incorporated during film growth. The LEDs were fabricated using ion beam epitaxy with an electric mirror sputtering-type metal ion source in an ultrahigh vacuum. Electroluminescence was observed from the LEDs under both forward and reverse biases. Each luminescence line corresponded well to the intra-4f transitions of Er+3 ions with almost single local coordination. The electroluminescence quenching factor with temperature under a forward bias was similar to that for photoluminescence. Sharp luminescence was, however, still observed even at room temperature under a forward bias. Under a reverse bias, strong electroluminescence was observed at room temperature without quenching.
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1 54 μm photoluminescence of in situ erbium oxygen co doped Silicon Films grown by ion beam epitaxy
Journal of Applied Physics, 1995Co-Authors: Morito Matsuoka, Shun‐ichi TohnoAbstract:Erbium‐doped Silicon Films are grown by ion‐beam epitaxy using an electric‐mirror sputtering‐type metal ion source in an ultrahigh vacuum. In situ erbium doping with concentrations ranging from 1×1016 to 6×1020 cm−3 is achieved by sputtering the erbium metal pellet with ions extracted from the Silicon metal ion source. The oxygen concentration in the Films, which is closely related to the effective luminescence of erbium in Silicon, is also controlled in situ over the range from below 1×1018 to 2×1020 cm−3 by using argon gases containing 1 ppb–100 ppm of oxygen impurities. The erbium incorporation efficiency drastically increases (by two or more orders of magnitude) when oxygen is contained in the argon gas during film growth. Erbium segregation is well suppressed by the oxidation. Photoluminescence with a wavelength of 1.54 μm is clearly observed in as‐deposited Films grown typically at 500 °C with argon gas containing 5 ppm of oxygen. The maximum luminescence intensity is obtained at an erbium concentra...
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1 54 μm wavelength emission of erbium doped Silicon Films grown by ion beam epitaxy using sputtering type metal ion source
Applied Physics Letters, 1995Co-Authors: Morito Matsuoka, Shun‐ichi TohnoAbstract:Erbium‐doped Silicon Films are grown by ion beam epitaxy using a newly developed electric‐mirror sputtering‐type metal ion source in an ultrahigh vacuum. A precise and steep profile of the erbium concentration, ranging from 1×1016 to 6×1020 cm−3, is achieved in situ by sputtering the erbium metal pellet with ions extracted from the Silicon ion source. The oxygen concentration in the Films, which is important to effective luminescence of erbium in Silicon, is controlled in situ in the range from below 1×1018 to 2×1020 cm−3 by using argon gases containing oxygen impurities ranging from 1 ppb to 100 ppm. The oxygen concentration trapped in the Silicon Films strongly depends on the erbium concentration doped in the Films. The erbium atoms are selectively oxidized in the host Silicon film. As a result, the photoluminescence of 1.54 μm wavelength light is clearly observed in as‐deposited Films.
