The Experts below are selected from a list of 75213 Experts worldwide ranked by ideXlab platform
Hideki Matsumura - One of the best experts on this subject based on the ideXlab platform.
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suppresSion of the epitaxial growth of Si films in Si heterojunction solar cells by the formation of ultra thin oxide layers
Current Applied Physics, 2016Co-Authors: Keisuke Ohdaira, Takafumi Oikawa, Koichi Higashimine, Hideki MatsumuraAbstract:Abstract The epitaxial growth of Silicon (Si) films during the catalytic chemical vapor depoSition (Cat-CVD) of intrinSic amorphous Si (i-a-Si) pasSivation films on crystalline Si (c-Si) wafers is suppressed by the oxidation of c-Si surfaces Simply by dipping the c-Si wafers in hydrogen peroxide (H 2 O 2 ). This oxidation treatment is also effective for (111)-oriented c-Si surfaces particularly at high a-Si depoSition temperatures. The suppresSion of the epitaxial growth leads to the better effective minority carrier lifetime (τ eff ) of c-Si wafers pasSivated with Cat-CVD i-a-Si films. SHJ solar cells show remarkably high open-circuit voltage ( V oc ) exceeding 0.7 V. These results clearly show the effectiveness of the insertion of SiO x layers on the improvement in Cat-CVD a-Si/c-Si interfaces.
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drastic reduction in surface recombination velocity of crystalline Silicon by surface treatment uSing catalytically generated radicals
Solar Energy Materials and Solar Cells, 2011Co-Authors: Hideki Matsumura, Motoharu Miyamoto, Koichi Koyama, Keisuke OhdairaAbstract:A method of reducing surface recombination velocities (SRVs) of crystalline Silicon (c-Si) wafers is presented for the case when c-Si surfaces are pasSivated by amorphous Si (a-Si) thin films. It is demonstrated that the surface treatment of c-Si wafers prior to a-Si depoSition, uSing hydrogen atoms generated by catalytic reaction of hydrogen gas with heated catalyzer, lowers SRV effectively, and that SRV is drastically reduced to less than 3 cm/s when a small amount of doping impurity is added during atomic hydrogen treatment.
Keisuke Ohdaira - One of the best experts on this subject based on the ideXlab platform.
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suppresSion of the epitaxial growth of Si films in Si heterojunction solar cells by the formation of ultra thin oxide layers
Current Applied Physics, 2016Co-Authors: Keisuke Ohdaira, Takafumi Oikawa, Koichi Higashimine, Hideki MatsumuraAbstract:Abstract The epitaxial growth of Silicon (Si) films during the catalytic chemical vapor depoSition (Cat-CVD) of intrinSic amorphous Si (i-a-Si) pasSivation films on crystalline Si (c-Si) wafers is suppressed by the oxidation of c-Si surfaces Simply by dipping the c-Si wafers in hydrogen peroxide (H 2 O 2 ). This oxidation treatment is also effective for (111)-oriented c-Si surfaces particularly at high a-Si depoSition temperatures. The suppresSion of the epitaxial growth leads to the better effective minority carrier lifetime (τ eff ) of c-Si wafers pasSivated with Cat-CVD i-a-Si films. SHJ solar cells show remarkably high open-circuit voltage ( V oc ) exceeding 0.7 V. These results clearly show the effectiveness of the insertion of SiO x layers on the improvement in Cat-CVD a-Si/c-Si interfaces.
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drastic reduction in surface recombination velocity of crystalline Silicon by surface treatment uSing catalytically generated radicals
Solar Energy Materials and Solar Cells, 2011Co-Authors: Hideki Matsumura, Motoharu Miyamoto, Koichi Koyama, Keisuke OhdairaAbstract:A method of reducing surface recombination velocities (SRVs) of crystalline Silicon (c-Si) wafers is presented for the case when c-Si surfaces are pasSivated by amorphous Si (a-Si) thin films. It is demonstrated that the surface treatment of c-Si wafers prior to a-Si depoSition, uSing hydrogen atoms generated by catalytic reaction of hydrogen gas with heated catalyzer, lowers SRV effectively, and that SRV is drastically reduced to less than 3 cm/s when a small amount of doping impurity is added during atomic hydrogen treatment.
Michael Burrows - One of the best experts on this subject based on the ideXlab platform.
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effect of texturing and surface preparation on lifetime and cell performance in heterojunction Silicon solar cells
Solar Energy Materials and Solar Cells, 2008Co-Authors: Matthew Edwards, Stuart Bowden, Michael BurrowsAbstract:Heterojunction solar cells have potential for very high device voltages and currents, yet this relies on correct preparation of wafer surfaces prior to amorphous Silicon (a-Si) depoSition. This paper investigates the preparation of wafer surfaces by NaOH texturing and thinning prior to a-Si intrinSic layer depoSition. It is found that with a CP etch or low-temperature anneal, and with correct depoSition parameters, effective wafer lifetimes in excess of 1 ms can be achieved, indicating excellent surface pasSivation. Low reflectance achieved following wafer texturing along with high wafer lifetime led to efficiencies in finished devices as high as 17.6%.
Wolfram Jaegermann - One of the best experts on this subject based on the ideXlab platform.
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Silicon organic pigment material hybrids for photovoltaic application
Solar Energy Materials and Solar Cells, 2007Co-Authors: Thomas Mayer, Martin Kunst, C Kelting, Derck Schlettwein, Dieter Wohrle, O Abdallah, S Makarov, U. Weiler, Wolfram JaegermannAbstract:Hybrid materials of Silicon and organic dyes have been investigated for posSible application as photovoltaic material in thin film solar cells. High converSion efficiency is expected from the combination of the advantages of organic dyes for light absorption and those of Silicon for charge carrier separation and transport. Low temperature remote hot wire chemical vapor depoSition (HWCVD) was developed for microcrystalline Silicon (mc-Si) depoSition uSing SiH4/H2 mixtures. As model dyes zinc phthalocyanines have been evaporated from Knudsen type sources. Layers of dye on mc-Si and mc-Si on dye films, and compoSites of Simultaneously and sequentially depoSited Si and dye have been prepared and characterized. Raman, absorption, and photoemisSion spectroscopy prove the stability of the organic molecules against the rough HWCVD-Si process. TranSient microwave conductivity (TRMC) indicates good electronic quality of the mc-Si matrix. Energy transfer from dye to Si is indicated indirectly by luminescence and directly by photoconductivity measurements. FxZnPc pigments with x ¼ 0,4,8,16 have been syntheSized, purified and adsorbed onto H-terminated Si(1 1 1) for electronic state line up determination by photoelectron spectroscopy. For x ¼ 4 and 8 the dye frontier orbitals line up symmetrically versus the Si energy gap offering Similar energetic driving forces for electron and hole injection, which is conSidered optimum for bulk senSitization and indicates a direction to improve the optoelectronic coupling of the organic dyes to Silicon. r 2007 Elsevier B.V. All rights reserved.
Brian J Landi - One of the best experts on this subject based on the ideXlab platform.
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high performance Silicon free standing anodes fabricated by low pressure and plasma enhanced chemical vapor depoSition onto carbon nanotube electrodes
Journal of Power Sources, 2013Co-Authors: Michael W Forney, Roberta A Dileo, Alan D Raisanen, Matthew J Ganter, Jason Staub, Reginald E Rogers, Richard D Ridgley, Brian J LandiAbstract:Abstract High capacity Silicon and alternative current collectors are being evaluated as a viable approach to increase the energy denSity of lithium ion batteries. Presently, Silicon is depoSited onto lightweight Single-walled carbon nanotube (SWCNT) current collectors by low-pressure chemical vapor depoSition (LPCVD) and plasma-enhanced chemical vapor depoSition (PECVD) to form Si-SWCNT free-standing anodes. The electrode morphology is characterized by scanning electron microscopy (SEM) and Raman spectroscopy, and the electrochemical performance is studied for each CVD method at Silicon weight loadings between 25% and 70%. Results demonstrate that PECVD fabricated Si-SWCNT anodes outperform LPCVD fabricated anodes, with electrode extraction capacities as high as 2500 mAh g −1 . When only the Si mass is conSidered, PECVD-Si-SWCNT anodes have up to 2x higher extraction capacities than LPCVD-Si-SWCNT anodes at low Si loadings. The highest Si-only extraction capacity measured was 3780 mAh g −1 . Full cells were demonstrated to have stable cycling for 100 cycles. Postmortem analySis (via SEM and Raman) reveals that PECVD-Si-SWCNT anodes undergo more Significant morphological and crystallographic changes during cycling than LPCVD-Si-SWCNT anodes. This work demonstrates that the choice of CVD method for Si depoSition onto SWCNT current collectors greatly impacts the resulting electrode morphology, which, in turn, affects the electrochemical performance.