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Sample records for efficiency triple-junction amorphous

  1. Triple-junction amorphous silicon alloy solar cell with 14.6{percent} initial and 13.0{percent} stable conversion efficiencies

    SciTech Connect

    Yang, J.; Banerjee, A.; Guha, S.

    1997-06-01

    We have achieved 14.6{percent} initial and 13.0{percent} stable conversion efficiencies using an amorphous silicon-based alloy in a spectrum-splitting, triple-junction structure. These efficiencies have been confirmed independently by the National Renewable Energy Laboratory. Key factors leading to this major advance include improvements made in the low band-gap amorphous silicon{endash}germanium alloy cell, the pn tunnel junction between the component cells, and the top conducting oxide. {copyright} {ital 1997 American Institute of Physics.}

  2. A record setting amorphous silicon alloy triple-junction solar cell with 14.6{percent} initial and 12.8{percent} stable efficiencies

    SciTech Connect

    Yang, J.; Banerjee, A.; Guha, S.

    1997-02-01

    World record 14.6{percent} initial and 12.8{percent} stable conversion efficiencies have been achieved using amorphous silicon based alloy in a spectrum-splitting, triple-junction structure. This performance exceeds our previous record of 13.2{percent} initial and 11.8{percent} stable efficiencies and establishes a new milestone toward reaching the 15{percent} stable module goal. Key factors leading to this major advance include: (a) Improvement in the low bandgap amorphous silicon-germanium component cell that resulted in enhanced red response and provided desired current mismatching, (b) improvement in the pn tunnel junction between component cells by incorporating microcrystalline p and n layers in a multilayered structure that resulted in reduced optical and electrical losses, and (c) improvement in the top conducting oxide that resulted in reduced absorption and enhanced blue response without increasing the top cell thickness. Details of these advances along with light-soaking data for high efficiency cells will be discussed. {copyright} {ital 1997 American Institute of Physics.}

  3. Triple-Junction Hybrid Tandem Solar Cells with Amorphous Silicon and Polymer-Fullerene Blends

    PubMed Central

    Kim, Taehee; Kim, Hyeok; Park, Jinjoo; Kim, Hyungchae; Yoon, Youngwoon; Kim, Sung-Min; Shin, Chonghoon; Jung, Heesuk; Kim, Inho; Jeong, Doo Seok; Kim, Honggon; Kim, Jin Young; Kim, BongSoo; Ko, Min Jae; Son, Hae Jung; Kim, Changsoon; Yi, Junsin; Han, Seunghee; Lee, Doh-Kwon

    2014-01-01

    Organic-inorganic hybrid tandem solar cells attract a considerable amount of attention due to their potential for realizing high efficiency photovoltaic devices at a low cost. Here, highly efficient triple-junction (TJ) hybrid tandem solar cells consisting of a double-junction (DJ) amorphous silicon (a-Si) cell and an organic photovoltaic (OPV) rear cell were developed. In order to design the TJ device in a logical manner, a simulation was carried out based on optical absorption and internal quantum efficiency. In the TJ architecture, the high-energy photons were utilized in a more efficient way than in the previously reported a-Si/OPV DJ devices, leading to a significant improvement in the overall efficiency by means of a voltage gain. The interface engineering such as tin-doped In2O3 deposition as an interlayer and its UV-ozone treatment resulted in the further improvement in the performance of the TJ solar cells. As a result, a power conversion efficiency of 7.81% was achieved with an open-circuit voltage of 2.35 V. The wavelength-resolved absorption profile provides deeper insight into the detailed optical response of the TJ hybrid solar cells. PMID:25412648

  4. The Environmental Performance at Low Intensity, Low Temperature (LILT) of High Efficiency Triple Junction Solar Cells

    NASA Technical Reports Server (NTRS)

    Stella, Paul M.; Mueller, Robert; Davis, Gregory; Distefano, Salvador

    2004-01-01

    A number of JPL missions, either active or in the p l d g stages, require the accurate LILT flew intensity - low temperate) climate of triple-junction solar. Although triple ignition LILT performance was reported as recently as 2002, there has been an evolutionary advance in cell technology by both U.S. space cell manufacturers that, for mission design purposes, effectively obsoletes the earlier data. As a result, JPL initiated a program to develop a database for the LILT performance of the new high performance triple junction solar cells. JPL obtained Emcore Advanced triple Juntion CIC assemblies and Spectrolab Ultra Triple Junction CIC assemblies. These cells were tested at temperature-intensity ranges designed to cover applications between 1 and 5.18 AU solar distances. 1 MeV electron irradiation from 25 E14 to 1 El5 w were performed on the cells to evaluate the combined effect of particulate radiation and LILT conditions. The effect of LILT conditions was observed to incur an increase in the variation of cell performances such that at simulted 5.18 AU conditions the average performance was approximately 30% with the best cells measuring between 32 and 34% efficiency. The 30% average efficiency compares with approximately 25% average efficiency measured on earlier technology triple junction solar cells.

  5. Triple-junction amorphous silicon alloy PV manufacturing plant of 5 MW annual capacity

    SciTech Connect

    Guha, S.; Yang, J.; Banerjee, A.

    1997-12-31

    A spectral-splitting, triple-junction a-Si alloy solar cell processor has been designed, built and optimized. A roll-to-roll process has been used to deposit two layers of back reflector, a triple-cell structure with nine layers of a-Si and a-SiGe alloys and a single layer of antireflection coating consecutively on a half-a-mile roll of stainless steel. The coated web is next slabbed and processed to make a variety of products. The design of the machine and processes used incorporate several key features developed for improving cell efficiency. In order to reduce manufacturing cost, higher deposition rates and thinner cells than are used in R and D have been used. The back reflector also consists of Al/ZnO rather than Ag/ZnO. Large-scale production has begun, and products are being shipped for a wide range of applications.

  6. Very High Efficiency Triple Junction Solar Cells Based On (AL)InGaP Compounds

    NASA Astrophysics Data System (ADS)

    Gori, Gabriele; Campesato, Roberta; Casale, Maria Cristina; Gabetta, Giuseppe

    2011-10-01

    In this paper we report the theoretical and experimental results related to the use of Aluminium Gallium Indium Phosphide (AlInGaP) as substitute of Gallium Indium Phosphide (InGaP) semiconductor, in the realization of high efficiency triple junction solar cells for space applications. The (Al)InGaP/GaAs/Ge solar cells have been modelled and manufactured on standard and thin Germanium wafers; the measurements under AM0 spectrum 25 °C, showed efficiencies above 30% both on standard and thin Ge wafers.

  7. Development of high stable-efficiency, triple-junction a-Si alloy solar cells. Annual subcontract report, July 18, 1994--July 17, 1995

    SciTech Connect

    Deng, X.

    1996-02-01

    This report describes work performed by Energy Conversion Devices, Inc. (ECD) under a 3-year, cost-shared amorphous silicon (a-Si) research program to develop advanced technologies and to demonstrate stable 14%-efficient, triple-junction a-Si alloy solar cells. The technologies developed under the program will then be incorporated into ECD`s continuous roll-to-roll deposition process to further enhance ECD`s photovoltaic manufacturing technology. In ECD`s solar cell design, triple-junction a-Si alloy solar cells are deposited onto stainless-steel substrates coated with Ag/ZnO back-reflector layers. This type of cell design enabled ECD to use a continuous roll- to-roll deposition process to manufacture a-Si PV materials in high volume at low cost. Using this cell design, ECD previously achieved 13.7% initial solar cell efficiency using the following features: (1) a triple-junction, two-band-gap, spectrum-splitting solar cell design; (2) a microcrystalline silicon p-layer; (3) a band-gap-profiled a- SiGe alloy as the bottom cell i-layer; (4) a high-performance AgZnO back-reflector; and (5) a high-performance tunnel junction between component cells. ECD also applied the technology into its 2-MW/yr a- Si production line and achieved the manufacturing of 4-ft{sup 2} PV modules with 8% stable efficiency. During this program, ECD is also further advancing its existing PV technology toward the goal of 14% stable solar cells by performing the following four tasks: (1) improving the stability of the intrinsic a-Si alloy materials; (2) improving the quality of low-band-gap a-SiGe alloy; (3) improving p{sup +} window layers, and (4) developing high stable-efficiency triple-junction a-Si alloy solar cells.

  8. Performance of High-Efficiency Advanced Triple-Junction Solar Panels for the LILT Mission Dawn

    NASA Technical Reports Server (NTRS)

    Fatemi, Navid S.; Sharma, Surya; Buitrago, Oscar; Sharps, Paul R.; Blok, Ron; Kroon, Martin; Jalink, Cees; Harris, Robin; Stella, Paul; Distefano, Sal

    2005-01-01

    NASA's Discovery Mission Dawn is designed to (LILT) conditions. operate within the solar system's Asteroid belt, where the large distance from the sun creates a low-intensity, low-temperature (LILT) condition. To meet the mission power requirements under LlLT conditions, very high-efficiency multi-junction solar cells were selected to power the spacecraft to be built by Orbital Sciences Corporation (OSC) under contract with JPL. Emcore's InGaP/InGaAs/Ge advanced triple-junction (ATJ) solar cells, exhibiting an average air mass zero (AMO) efficiency of greater than 27.6% (one-sun, 28 C), were used to populate the solar panels [1]. The two solar array wings, to be built by Dutch Space, with 5 large- area panels each (total area of 36.4 sq. meters) are projected to produce between 10.3 kWe and 1.3 kWe of end-of life (EOL) power in the 1.0 to 3.0 AU range, respectively. The details of the solar panel design, testing and power analysis are presented.

  9. High efficiency triple-junction solar cells employing biomimetic antireflective structures

    NASA Astrophysics Data System (ADS)

    Chiu, Meng-Yih; Chang, Chia-Hua; Chang, Feng-Yu; Yu, Peichen

    2011-02-01

    In this work, we demonstrate a thorough device design, fabrication, characterization, and analysis of biomimetic antireflective structures implemented on a Ga0.5In0.5P/GaAs/Ge triple-junction solar cell. The sub-wavelength structures are fabricated on a silicon nitride passivation layer using polystyrene nanosphere lithography followed by anisotropic etching. The fabricated structures enhance optical transmission in the ultraviolet wavelength range, compared to a conventional single-layer antireflective coating (ARC). The transmission improvement contributes to the enhanced photocurrent, which is also verified by the external quantum efficiency characterization of fabricated solar cells. Under one-sun illumination, the short-circuit current of a cell with a biomimetic structures is enhanced by 24.1% and 2.2% due to much improved optical transmission and current matching, compared to cells without an ARC and with a conventional ARC, respectively. Further optimizations of the biomimetic structures including the periodicity and etching depth are conducted by performing comprehensive calculations based on a rigorous couple-wave analysis method.

  10. Efficient enhancement of hydrogen production by Ag/Cu2O/ZnO tandem triple-junction photoelectrochemical cell

    NASA Astrophysics Data System (ADS)

    Liu, Ying; Ren, Feng; Shen, Shaohua; Fu, Yanming; Chen, Chao; Liu, Chang; Xing, Zhuo; Liu, Dan; Xiao, Xiangheng; Wu, Wei; Zheng, Xudong; Liu, Yichao; Jiang, Changzhong

    2015-03-01

    Highly efficient semiconductor photoelectrodes for solar hydrogen production through photocatalytic water splitting are a promising and challenge solution to solve the energy problems. In this work, Ag/Cu2O/ZnO tandem triple-junction photoelectrode was designed and prepared. An increase of 11 times of photocurrent is achieved in the Ag/Cu2O/ZnO photoelectrode comparing to that of the Cu2O film. The high performance of the Ag/Cu2O/ZnO film is due to the optimized design of the tandem triple-junction structure, where the localized surface Plasmon resonance of Ag and the hetero-junctions efficiently absorb solar energy, produce, and separate electron-hole pairs in the photocathode.

  11. Development of a High Efficiency UVR/IRR Coverglass for Triple Junction Solar Cells

    NASA Technical Reports Server (NTRS)

    Russell, John; Jones, Glenn; Hall, James

    2007-01-01

    Cover glasses have been a necessary and integral part of space solar arrays since their inception. The main function of the cover glass is to protect the underlying solar cell from the harsh radiation environment of space. They are formed either from fused silica or specially formulated ceria doped glass types that are resistant to radiation damage, for example Pilkington's CMX, CMG, CMO. Solar cells have steadily increased in performance over the past years, from Silicon cells through textured Silicon cells to GaAs cells and the multijunction cells of today. The optimum coverglass solution for each of these cells has been different. The glass itself has also evolved. In some cases it has had its expansion coefficient matched to the cell substrate material, and in addition, added value has been derived from the application of thin film optical coatings to the coverglass. In the majority of cases this has taken the form of a single layer of MgF2 which acts as an antireflection coating. There are also conductive coatings to address electrostatic discharge issues (ESD) and Ultra Violet Reflective (UVR) and Infrared Reflective (IRR) coatings designed for thermal enhancement. Each type of coating can be applied singly or in combination. This paper describes a new type of UVR/IRR (or blue red reflector BRR) specifically designed for triple junction solar cells. For space applications, where radiation is the principal mechanism for removing heat from the satellite, it is the emittance and solar absorptance that primarily determine the temperature of the array. It is therefore essential that any coatings designed to have an effect on the temperature by reducing the solar absorption have a minimal effect on the overall emittance.

  12. Efficient enhancement of hydrogen production by Ag/Cu{sub 2}O/ZnO tandem triple-junction photoelectrochemical cell

    SciTech Connect

    Liu, Ying; Ren, Feng Chen, Chao; Liu, Chang; Xing, Zhuo; Liu, Dan; Xiao, Xiangheng; Wu, Wei; Zheng, Xudong; Liu, Yichao; Jiang, Changzhong; Shen, Shaohua; Fu, Yanming

    2015-03-23

    Highly efficient semiconductor photoelectrodes for solar hydrogen production through photocatalytic water splitting are a promising and challenge solution to solve the energy problems. In this work, Ag/Cu{sub 2}O/ZnO tandem triple-junction photoelectrode was designed and prepared. An increase of 11 times of photocurrent is achieved in the Ag/Cu{sub 2}O/ZnO photoelectrode comparing to that of the Cu{sub 2}O film. The high performance of the Ag/Cu{sub 2}O/ZnO film is due to the optimized design of the tandem triple-junction structure, where the localized surface Plasmon resonance of Ag and the hetero-junctions efficiently absorb solar energy, produce, and separate electron-hole pairs in the photocathode.

  13. Triple-junction thin-film silicon solar cell fabricated on periodically textured substrate with a stabilized efficiency of 13.6%

    NASA Astrophysics Data System (ADS)

    Sai, Hitoshi; Matsui, Takuya; Koida, Takashi; Matsubara, Koji; Kondo, Michio; Sugiyama, Shuichiro; Katayama, Hirotaka; Takeuchi, Yoshiaki; Yoshida, Isao

    2015-05-01

    We report a high-efficiency triple-junction thin-film silicon solar cell fabricated with the so-called substrate configuration. It was verified whether the design criteria for developing single-junction microcrystalline silicon (μc-Si:H) solar cells are applicable to multijunction solar cells. Furthermore, a notably high short-circuit current density of 32.9 mA/cm2 was achieved in a single-junction μc-Si:H cell fabricated on a periodically textured substrate with a high-mobility front transparent contacting layer. These technologies were also combined into a-Si:H/μc-Si:H/μc-Si:H triple-junction cells, and a world record stabilized efficiency of 13.6% was achieved.

  14. The epitaxial growth of high efficiency inverted metamorphic triple junction solar cell for CPV application

    NASA Astrophysics Data System (ADS)

    Jingfeng, Bi; Senlin, Li; Guanzhou, Liu; Meijia, Yang; Mingyang, Li; Weiping, Xiong; Minghui, Song; Guijiang, Lin; Wenjun, Chen; Duxiang, Wang

    2015-09-01

    In this paper, 3J-IMM solar cells were studied in comparison with 3J-LM solar cells grown by MOCVD. The structural characteristics were studied by HRXRD, HRTEM and SIMS, which showed a high crystal quality of the metamorphic sub-cell. The solar cell performance in terms of I-V curves and EQE was investigated between the different solar cells structures. The current of the IMM solar cell is almost equal to the LM ´monitor solar cell. Under AM 1.5D, 1000 suns conditions, an Isc of 14.29 A, Voc of 3.538 V, FF of 83.9 %, and an efficiency of 42.3 % were achieved for the 3J-IMM solar cell with a chip size of 1.0 cm2, which is an absolute 2.9% higher than that of a 3J-LM solar cell in conversion efficiency. The excess current contribution from the Ge bottom cell in the 3J-LM solar cells is eliminated, accompanied with a 0.3V increase in Voc for the 3J-IMM solar cells.

  15. Development of high, stable-efficiency triple-junction a-Si alloy solar cells. Final technical report

    SciTech Connect

    Deng, X.; Jones, S.J.; Liu, T.; Izu, M.

    1998-04-01

    This report summarizes Energy Conversion Devices, Inc.`s (ECD) research under this program. ECD researchers explored the deposition of a-Si at high rates using very-high-frequency plasma MHz, and compared these VHF i-layers with radio-frequency (RF) plasma-deposited i-layers. ECD conducted comprehensive research to develop a {mu}c-Si p{sup +} layer using VHF deposition process with the objectives of establishing a wider process window for the deposition of high-quality p{sup +} materials and further enhancing their performance of a-Si solar cells by improving its p-layers. ECD optimized the deposition of the intrinsic a-Si layer and the boron-doped {mu}c-Si p{sup +} layer to improve the V{sub oc}. Researchers deposited wide-bandgap a-Si films using high hydrogen dilution; investigated the deposition of the ZnO layer (for use in back-reflector) using a sputter deposition process involving metal Zn targets; and obtained a baseline fabrication for single-junction a-Si n-i-p devices with 10.6% initial efficiency and a baseline fabrication for triple-junction a-Si devices with 11.2% initial efficiency. ECD researchers also optimized the deposition parameters for a-SiGe with high Ge content; designed a novel structure for the p-n tunnel junction (recombination layer) in a multiple-junction solar cell; and demonstrated, in n-i-p solar cells, the improved stability of a-Si:H:F materials when deposited using a new fluorine precursor. Researchers investigated the use of c-Si(n{sup +})/a-Si alloy/Pd Schottky barrier device as a tool for the effective evaluation of photovoltaic performance on a-Si alloy materials. Through alterations in the deposition conditions and system hardware, researchers improved their understanding for the deposition of uniform and high-quality a-Si and a-SiGe films over large areas. ECD researchers also performed extensive research to optimize the deposition process of the newly constructed 5-MW back-reflector deposition machine.

  16. The Sinai triple junction revisited

    NASA Astrophysics Data System (ADS)

    Courtillot, Vincent; Armijo, Rolando; Tapponnier, Paul

    1987-09-01

    This paper is a summary of a more detailed analysis of the kinematics of the Sinai triple junction (Courtillot et al., 1987). Accurate kinematic data are lacking along the Red Sea and they can be supplemented by bathymetric, topographic and geological data pertaining to the three arms of the entirely continental Sinai triple junction. Motions across the northern Red Sea and along the Gulf of Elat are an order of magnitude larger than across the Gulf of Suez. The direction of motion there remains a major uncertainty. A possible kinematic model is highlighted, in which right-lateral strike-slip motion and small pull-apart basins occur along the Gulf of Suez, in agreement with recent field observations in Egypt. Early Miocene is marked by major geodynamical changes all along the northern boundaries of the African and Indian plates. We suggest that rifting in the Arabian Sea, Gulf of Aden, Red Sea and Gulf of Suez was initiated at the end of the first phase of continental extrusion of Indochina, when the Tibetan plateau began to rise and spreading in the South China Sea came to a halt.

  17. Highly Efficient Hybrid Polymer and Amorphous Silicon Multijunction Solar Cells with Effective Optical Management.

    PubMed

    Tan, Hairen; Furlan, Alice; Li, Weiwei; Arapov, Kirill; Santbergen, Rudi; Wienk, Martijn M; Zeman, Miro; Smets, Arno H M; Janssen, René A J

    2016-03-16

    Highly efficient hybrid multijunction solar cells are constructed with a wide-bandgap amorphous silicon for the front subcell and a low-bandgap polymer for the back subcell. Power conversion efficiencies of 11.6% and 13.2% are achieved in tandem and triple-junction configurations, respectively. The high efficiencies are enabled by deploying effective optical management and by using photoactive materials with complementary absorption. PMID:26780260

  18. Time-resolved photoluminescence measurements for determining voltage-dependent charge-separation efficiencies of subcells in triple-junction solar cells

    SciTech Connect

    Tex, David M.; Ihara, Toshiyuki; Kanemitsu, Yoshihiko; Akiyama, Hidefumi; Imaizumi, Mitsuru

    2015-01-05

    Conventional external quantum-efficiency measurement of solar cells provides charge-collection efficiency for approximate short-circuit conditions. Because this differs from actual operating voltages, the optimization of high-quality tandem solar cells is especially complicated. Here, we propose a contactless method, which allows for the determination of the voltage dependence of charge-collection efficiency for each subcell independently. By investigating the power dependence of photoluminescence decays, charge-separation and recombination-loss time constants are obtained. The upper limit of the charge-collection efficiencies at the operating points is then obtained by applying the uniform field model. This technique may complement electrical characterization of the voltage dependence of charge collection, since subcells are directly accessible.

  19. Recent improvements in amorphous silicon-based multijunction modules

    SciTech Connect

    Arya, R.R.; Bennett, M.; Yang, L.; Newton, J.; Li, Y.M.; Maley, N.; Fieselmann, B.; Chen, L.F.; Rajan, K.; Wilczynski, A.; Wood, G. )

    1994-06-30

    Advances in intrinsic amorphous silicon and in amorphous silicon carbon alloys have resulted in thin single junction devices with V[sub oc]'s over 1.0 volts and excellent stability with both i-layer materials. Incorporation of improved a-Si:H i-layers and thin microcrystalline n-layers in a-Si/a-Si/a-SiGe triple junction modules has resulted in large area triple junction modules with initial efficiencies as high as 11.35%. These modules exhibit a degradation of [similar to]20% after 1000 hours of light-soaking resulting in [similar to]9% stable modules.

  20. Research on stable, high-efficiency amorphous silicon multijunction modules

    SciTech Connect

    Banerjee, A.; Chen, E.; Clough, R.; Glatfelter, T.; Guha, S.; Hammond, G.; Hopson, M.; Jackett, N.; Lycette, M.; Noch, J.; Palmer, T.; Pawlikiewicz, A.; Rosenstein, I.; Ross, R.; Wolf, D.; Xu, X.; Yang, J.; Younan, K.

    1992-04-01

    This report describes the progress made during Phase 1 of research and development program to obtain high-efficiency amorphous silicon alloy multijunction modules. Using a large-area deposition system, double-and triple-junction cells were made on stainless steel substrates of over 1 ft{sup 2} area with Ag and ZnO predeposited back reflector. Modules of over 1 ft{sup 2} were produced with between 9.2% and 9.9 initial aperture-area efficiencies as measured under a USSC Spire solar simulator. Efficiencies as measured under the NREL Spire solar simulator were found to be typically 15% to 18% lower. The causes for this discrepancy are now being investigated. The modules show about 15% degradation after 600 hours of one-sun illumination at 50{degrees}C. To optimize devices for higher stabilized efficiency, a new method was developed by which the performance of single-junction cells after long-term, one-sun exposure at 50{degrees}C can be predicted by exposing cells to short-term intense light at different temperatures. This method is being used to optimize the component cells of the multijunction structure to obtain the highest light-degraded efficiency.

  1. Quaternary Evolution of Karliova Triple Junction

    NASA Astrophysics Data System (ADS)

    Sançar, Taylan; Zabcı, Cengiz; Akyüz, H. Serdar

    2013-04-01

    The arguments to explain Quaternary evolution of Karlıova Triple Junction (KTJ) depends upon two different analogue models. The compressional type of Prandtl Cell Model (PCM) and 60 km wide shear zone with concomitant counter clockwise block rotation used to modelled for west and east of the KTJ respectively. The data for the model of west of the KTJ acquired by extensive field studies, and quantified geomorphic features. Compressional PCM put forward that behavior of slip lines controlled by boundary faults. But the model is not enough to explain slip distribution, age relation of them. At west of the KTJ boundary faults presented by eastern most segments of the North Anatolian Fault Zone (NAFZ) and the East Anatolian Fault Zone (EAFZ). Slip lines, however, presented by Bahçeli and Toklular faults. Both field studies and morphometric analyses undisputedly set forth that there are two different fault types between the NAFZ and EAFZ. The most strain loaded fault type, which are positioned near the NAFZ, start as a strike-slip fault and when it turn to SE its sense of motion change to oblique normal due to changing orientation of principal stress axes. The new orientation of stress axes exposed in the field as a special kind of caprock -cuesta-. The younger slip lines formed very close to junction point and accommodate less slip. Even though slip trajectories started from the boundary faults in compressional PCM, at the west of KTJ, right lateral trajectories more clearly formed close the NAFZ and left lateral trajectories, relatively less strain loaded fault type, are poorly formed close the EAFZ . We think that, this differences between KTJ and compressional PCM result from the distinction of velocity of boundary faults. East of the KTJ governed by completely different mechanism. The region controlled two main fault systems. The Varto Fault Zone (VFZ), the eastern branch of the KTJ, and Murat Fault (MF) delimited the region from north and south respectively. The

  2. Research on stable, high-efficiency, amorphous silicon multijunction modules

    SciTech Connect

    Catalano, A.; Bennett, M.; Chen, L.; D'Aiello, R.; Fieselmann, B.; Li, Y.; Newton, J.; Podlesny, R.; Yang, L. . Thin Film Div.)

    1992-08-01

    This report describes work to demonstrate a multijunction module with a stabilized'' efficiency (600 h, 50{degrees}C, AM1.5) of 10.5%. Triple-junction devices and modules using a-Si:H alloys with carbon and germanium were developed to meet program goals. ZnO was used to provide a high optical transmission front contact. Proof of concept was obtained for several important advances deemed to be important for obtaining high (12.5%) stabilized efficiency. They were (1) stable, high-quality a-SiC:H devices and (2) high-transmission, textured ZnO. Although these developments were not scaled up and included in modules, triple-junction module efficiencies as high as 10.85% were demonstrated. NREL measured 9.62% and 9.00% indoors and outdoors, respectively. The modules are expected to lose no more than 20% of their initial performance. 28 refs.

  3. Research on stable, high-efficiency, amorphous silicon multijunction modules. Final subcontract report, 1 May 1990--30 June 1993

    SciTech Connect

    Arya, R.R.; Bennett, M.; Chen, L.; Fieselmann, B.; Li, Y.; Maley, N.; Newton, J.; Podlesny, R.; Yang, L.

    1994-06-01

    This report describes work performed dudng the period 1 July 1992 through 30 June 1993. Dudng this period, major improvements were achieved in the stabilized conversion efficiency of triple-junction modules. These resulted in the demonstration of triple-junction initial conversion efficiency of 11.3% and stabilized conversion efficiency of approximately 9%. Significant advances were made in the deposition of a-Si:H intrinsic layers that led to higher open-circuit voltage and improved stability. Thin microcrystalline n-layers were developed and scaled up for the recombination junctions in triple-junction modules that resulted in higher open-circuit voltage and fill factors. These improvements resulted in the demonstration of a-Si/a-Si/a-SiGe triple-junction modules with initial conversion efficiencies as high as 11.35% and ``stabilized`` efficiencies of about 9%.

  4. High-Efficiency Amorphous Silicon Alloy Based Solar Cells and Modules; Final Technical Progress Report, 30 May 2002--31 May 2005

    SciTech Connect

    Guha, S.; Yang, J.

    2005-10-01

    The principal objective of this R&D program is to expand, enhance, and accelerate knowledge and capabilities for development of high-efficiency hydrogenated amorphous silicon (a-Si:H) and amorphous silicon-germanium alloy (a-SiGe:H) related thin-film multijunction solar cells and modules with low manufacturing cost and high reliability. Our strategy has been to use the spectrum-splitting triple-junction structure, a-Si:H/a-SiGe:H/a-SiGe:H, to improve solar cell and module efficiency, stability, and throughput of production. The methodology used to achieve the objectives included: (1) explore the highest stable efficiency using the triple-junction structure deposited using RF glow discharge at a low rate, (2) fabricate the devices at a high deposition rate for high throughput and low cost, and (3) develop an optimized recipe using the R&D batch large-area reactor to help the design and optimization of the roll-to-roll production machines. For short-term goals, we have worked on the improvement of a-Si:H and a-SiGe:H alloy solar cells. a-Si:H and a-SiGe:H are the foundation of current a-Si:H based thin-film photovoltaic technology. Any improvement in cell efficiency, throughput, and cost reduction will immediately improve operation efficiency of our manufacturing plant, allowing us to further expand our production capacity.

  5. Grain boundary and triple junction diffusion in nanocrystalline copper

    SciTech Connect

    Wegner, M. Leuthold, J.; Peterlechner, M.; Divinski, S. V.; Song, X.; Wilde, G.

    2014-09-07

    Grain boundary and triple junction diffusion in nanocrystalline Cu samples with grain sizes, 〈d〉, of ∼35 and ∼44 nm produced by spark plasma sintering were investigated by the radiotracer method using the {sup 63}Ni isotope. The measured diffusivities, D{sub eff}, are comparable with those determined previously for Ni grain boundary diffusion in well-annealed, high purity, coarse grained, polycrystalline copper, substantiating the absence of a grain size effect on the kinetic properties of grain boundaries in a nanocrystalline material at grain sizes d ≥ 35 nm. Simultaneously, the analysis predicts that if triple junction diffusion of Ni in Cu is enhanced with respect to the corresponding grain boundary diffusion rate, it is still less than 500⋅D{sub gb} within the temperature interval from 420 K to 470 K.

  6. Simulation of the Mars Surface Solar Spectra for Optimized Performance of Triple-Junction Solar Cells

    NASA Technical Reports Server (NTRS)

    Edmondson, Kenneth M.; Joslin, David E.; Fetzer, Chris M.; King, RIchard R.; Karam, Nasser H.; Mardesich, Nick; Stella, Paul M.; Rapp, Donald; Mueller, Robert

    2007-01-01

    The unparalleled success of the Mars Exploration Rovers (MER) powered by GaInP/GaAs/Ge triple-junction solar cells has demonstrated a lifetime for the rovers that exceeded the baseline mission duration by more than a factor of five. This provides confidence in future longer-term solar powered missions on the surface of Mars. However, the solar cells used on the rovers are not optimized for the Mars surface solar spectrum, which is attenuated at shorter wavelengths due to scattering by the dusty atmosphere. The difference between the Mars surface spectrum and the AM0 spectrum increases with solar zenith angle and optical depth. The recent results of a program between JPL and Spectrolab to optimize GaInP/GaAs/Ge solar cells for Mars are presented. Initial characterization focuses on the solar spectrum at 60-degrees zenith angle at an optical depth of 0.5. The 60-degree spectrum is reduced to 1/6 of the AM0 intensity and is further reduced in the blue portion of the spectrum. JPL has modeled the Mars surface solar spectra, modified an X-25 solar simulator, and completed testing of Mars-optimized solar cells previously developed by Spectrolab with the modified X-25 solar simulator. Spectrolab has focused on the optimization of the higher efficiency Ultra Triple-Junction (UTJ) solar cell for Mars. The attenuated blue portion of the spectrum requires the modification of the top sub-cell in the GaInP/GaAs/Ge solar cell for improved current balancing in the triple-junction cell. Initial characterization confirms the predicted increase in power and current matched operation for the Mars surface 60-degree zenith angle solar spectrum.

  7. The progress of large area GaInP2/GaAs/Ge triple junction cell development at Spectrolab

    SciTech Connect

    Chiang, P.K.; Krut, D.; Cavicchi, B.T.

    1995-10-01

    In this paper the authors report the successful fabrication of large area, monolithic triple junction, n on p, GaInP2/GaAs/Ge cells. The highest open circuit voltage and cell efficiency (cell area: 4.078 sq cm) were measured at 2.573 V and 23.3%, respectively, under 1 sun, AMO illumination. To the authors knowledge, this is the highest single crystal, monolithic, two terminal triple junction cell efficiency demonstrated. In addition, excellent uniformity across a 3 inch diameter Ge substrates has also been achieved. An average cell efficiency of 22.8% across the 3 inch diameter wafer has been measured. They have also successfully fabricated welded cell-interconnect-cover (CIC) assemblies using these triple junction devices. The highest CIC efficiency was 23.2% (bare cell efficiency was 23.3%). The average efficiency for 25 CICs was 21.8%, which is very comparable to the 22.0% average bare cell efficiency before they were fabricated into the CICs. Finally, the authors have measured temperature coefficient and 1 MeV electron irradiation data. These will be presented in the paper.

  8. The progress of large area GaInP2/GaAs/Ge triple junction cell development at Spectrolab

    NASA Technical Reports Server (NTRS)

    Chiang, P. K.; Krut, D.; Cavicchi, B. T.

    1995-01-01

    In this paper we report the successful fabrication of large area, monolithic triple junction, n on p, GaInP2/GaAs/Ge cells. The highest open circuit voltage and cell efficiency (cell area: 4.078 sq cm) were measured at 2.573 V and 23.3%, respectively, under 1 sun, AMO illumination. To our knowledge, this is the highest single crystal, monolithic, two terminal triple junction cell efficiency demonstrated. In addition, excellent uniformity across a 3 inch diameter Ge substrates has also been achieved. An average cell efficiency of 22.8% across the 3 inch diameter wafer has been measured. We have also successfully fabricated welded cell-interconnect-cover (CIC) assemblies using these triple junction devices. The highest CIC efficiency was 23.2% (bare cell efficiency was 23.3%). The average efficiency for 25 CICs was 21.8%, which is very comparable to the 22.0% average bare cell efficiency before they were fabricated into the CICs. Finally, we have measured temperature coefficient and 1 MeV electron irradiation data. These will be presented in the paper.

  9. Advances in amorphous silicon alloy multijunction cells and modules

    SciTech Connect

    Guha, S.; Yang, J.; Banerjee, A.; Glatfelter, T.; Hoffman, K.; Xu, X.

    1996-01-01

    We discuss the research directions taken to improve the stable efficiency of amorphous silicon alloy multijunction modules. Use of hydrogen dilution during deposition has resulted in improvement of initial efficiency and stability of the component cells in the triple-junction structure. An innovative laser-interconnected module design has resulted in the reduction of optical and electrical losses in the module down to 1{percent}. {copyright} {ital 1996 American Institute of Physics.}

  10. Triple junctions and multi-directional extension of the lithosphere

    NASA Astrophysics Data System (ADS)

    Gerya, Taras; Burov, Evgenii

    2016-04-01

    Triple junctions are among the most remarkable features of global plate tectonics but their nucleation and evolution remains debatable. Divergent (R-R-R) triple junctions (at 120o and T junctions) are particular ones since their stability depends on the exact values of the relative velocities of multi-directional plate motions and hence is strongly affected by plate rheology and processes of crustal and lithospheric accretion. It is commonly accepted (although not quantitatively tested) that the geometry and stability of R-R-R triple junctions should be related to the intuitive geometric considerations that 3-branch configurations should be more "stable" compared to >3-branch configurations (e.g. quadruple junctions) under conditions of long-term multi-directional extension on a 3D Earth surface. Indeed, it has been long-time suggested that triple junctions result from evolution of short-lived quadruple junctions, yet, without providing a consistent mechanical explanation or experimental demonstration of this process, due to the rheological complexity of the breaking lithosphere subsequently subjected to complex oceanic crustal and lithospheric accretion processes. Therefore, a complete 3D thermo-mechanically consistent approach is needed to understand the processes of formation of multi-branch junctions. Here, we study numerically the processes of multi-branch junctions formation under condition of multi-directional lithospheric extension. We use high-resolution 3D numerical magmatic-thermo-mechanical experiments that take into account realistic thermo-rheological structure and rheology of the lithosphere and account for crustal and lithospheric accretion processes. We find that two major types of quadruple and triple junctions are formed under bi-directional or multidirectional far-field stress field: (1) plate rifting junctions are formed by the initial plate fragmentation and can be subsequently re-arranged into (2) oceanic spreading junctions controlled by the

  11. Tectonic setting of the Mendocino triple junction region

    SciTech Connect

    Clarke, S.H. Jr.; McLaughlin, R.J. ); Carver, G.A.; Burke, R.M.; McPherson, R.C. )

    1993-04-01

    Onshore and offshore geologic mapping coupled with topical investigations constrain the tectonic relations and geometry of active plate boundaries in the Mendocino triple junction region. Along the northern California coast and offshore, Gorda-North American plate convergence is reflected by youthful west- to northwest-verging thrust fault systems that extend to or near the plate interface at depth. Interplate coupling across a minimum breadth of 70--80 km is indicated by late Quaternary uplift and shortening rates, the nature and distribution of upper and lower plate seismicity, divergent trends in upper plate structures, and a history of large late Holocene earthquakes. Offshore seismic-reflection and seismicity data from the vicinity of the Mendocino fault (MF) show that the fault dips steeply to the north, and that the older, relatively rigid Pacific plate acts as a buttress against which the southern Gorda plate is being deformed. Onshore investigations show that the San Andreas fault zone (SAF) extends on land southeast of Point Delgada (at Whale Gulch), and is manifested along the north and northeast side of the King Range (KR) by north-northeast-vergent thrust faults. This thrust fault system may root into the steeply dipping offshore San Andreas fault. Faults of this system may include active, blind northeast-vergent thrusts that extend from a root zone beneath the King Range northward and upward into Franciscan Complex (Coastal belt) rocks along the north flank of the range. The southern Cascadia subduction zone megathrust intersects the Mendocino and San Andreas transform faults in the Mendocino triple junction. The upper crustal location of this intersection lies nearshore and/or landward along the north flank of the King Range. An area of focused rapid uplift and repeated coseismic growth (Mendocino Uplift) straddles the triple junction.

  12. Hydrothermal Exploration at the Chile Triple Junction - ABE's last adventure?

    NASA Astrophysics Data System (ADS)

    German, C. R.; Shank, T. M.; Lilley, M. D.; Lupton, J. E.; Blackman, D. K.; Brown, K. M.; Baumberger, T.; Früh-Green, G.; Greene, R.; Saito, M. A.; Sylva, S.; Nakamura, K.; Stanway, J.; Yoerger, D. R.; Levin, L. A.; Thurber, A. R.; Sellanes, J.; Mella, M.; Muñoz, J.; Diaz-Naveas, J. L.; Inspire Science Team

    2010-12-01

    In February and March 2010 we conducted preliminary exploration for hydrothermal plume signals along the East Chile Rise where it intersects the continental margin at the Chile Triple Junction (CTJ). This work was conducted as one component of our larger NOAA-OE funded INSPIRE project (Investigation of South Pacific Reducing Environments) aboard RV Melville cruise MV 1003 (PI: Andrew Thurber, Scripps) with all shiptime funded through an award of the State of California to Andrew Thurber and his co-PI's. Additional support came from the Census of Marine Life (ChEss and CoMarge projects). At sea, we conducted a series of CTD-rosette and ABE autonomous underwater vehicle operations to prospect for and determine the nature of any seafloor venting at, or adjacent to, the point where the the East Chile Rise subducts beneath the continental margin. Evidence from in situ sensing (optical backscatter, Eh) and water column analyses of dissolved CH4, δ3He and TDFe/TDMn concentrations document the presence of two discrete sites of venting, one right at the triple junction and the other a further 10km along axis, north of the Triple Junction, but still within the southernmost segment of the East Chile Rise. From an intercomparison of the abundance of different chemical signals we can intercompare likely characteristics of these differet source sites and also differentiate between them and the high methane concentrations released from cold seep sites further north along the Chile Margin, both with the CTJ region and also at the Concepcion Methane Seep Area (CMSA). This multi-disciplinary and international collaboration - involving scientists from Chile, the USA, Europe and Japan - can serve as an excellent and exciting launchpoint for wide-ranging future investigations of the Chile Triple Junction area - the only place on Earth where an oceanic spreading center is being actively subducted beneath a continent and also the only place on Earth where all known forms of deep

  13. Research on stable, high-efficiency amorphous silicon multijunction modules. Final subcontract report, 1 January 1991--31 August 1994

    SciTech Connect

    Guha, S.

    1994-10-01

    The principal objective of this program is to conduct research on semiconductor materials and non-semiconductor materials to enhance the performance of multibandgap, multijunction, large-area amorphous silicon-based alloy modules. The goal for this program is to demonstrate stabilized module efficiency of 12% for multijunction modules of area greater than 900 cm{sup 2}. Double-junction and triple-junction cells are made on Ag/ZnO back reflector deposited on stainless steel substrates. The top cell uses a-Si alloy; a-SiGe alloy is used for the i layer in the middle and the bottom cells. After evaporation of antireflection coating, silver grids and bus bars are put on the top surface, and the panel is encapsulated in an ethylene vinyl acetate (EVA)/Tefzel structure to make a one-square-foot monolithic module.

  14. Research on stable, high efficiency amorphous silicon multijunction modules

    SciTech Connect

    Catalano, A.; Arya, R.R.; Bennett, M.; Chen, L.; D'Aiello, R.; Fieselmann, B.; Li, Y.; Newton, J.; Podlesny, R.; Wiedeman, S.; Yang, L. . Thin Film Div.)

    1992-02-01

    Improvements towards a goal of a 12.5% initial triple-junction module efficiency require the use of a wide gap top-layer for improved open circuit voltage, higher transmission from the transparent front contact and more highly transmitting doped layers. To address the first issue, there has been continued development of a-SiC:H with the utilization of several novel feedstocks to control the atomic structure of the solid. These films have transport properties superior to the best results reported for a-SiC:H. Preliminary results with devices exhibits a stability comparable to a-Si:H, while previous results with a-SiC:H have generally shown for higher rates of degradation. Module fabrication has been refined to the extent that comparable module and small area device efficiencies are readily obtained. Despite the high initial efficiencies (9%--10%) obtained in 935 cm{sup 2} modules employing devices with 4000{Angstrom} thick middle junctions, higher than expected rates of degradation were found. The cause of the anomalous degradation was traced to shunts present in the device arising from defects in the tin oxide coating. NREL degradation results of triple-junction modules showed stabilized performance of the initial efficiency for modules prepared during the period in which shunts were a problem. 20 refs.

  15. Research on stable, high-efficiency amorphous silicon multijunction modules

    SciTech Connect

    Guha, S. )

    1992-09-01

    This report describes research on semiconductor and non-semiconductor materials to enhance the performance of multi-band-gap, multijunction panel with an area greater than 900 cm[sup 2] by 1992. Double-junction and triple-junction cells are mode on a Ag/ZnO back reflector deposited on stainless steel substrates. An a-SiGe alloy is used for the i-layer in the bottom and the middle cells; the top cell uses an amorphous silicon alloy. After the evaporation of an antireflection coating, silver grids and bus bars are put on the top surface and the panel is encapsulated in an ethylene vinyl acetate (EVA)/Tefzel structure to make a 1-ft[sup 2] monolithic module.

  16. Triple-Junction Solar Cell Design For Low Intensity Low Temperature Space Applications

    NASA Astrophysics Data System (ADS)

    Khorenko, V.; Strobl, G. F. X.; Hoheisel, R.; Dimroth, F.; Campesato, R.; Casale, M.; Baur, C.

    2011-10-01

    In this paper, we present the results of the electrical characterisation of triple-junction solar cells especially designed for low intensity low temperature (LILT) operation conditions. We show that by applying an appropriate choice of the front contact metallisation, by an additional passivation of the cell mesa edges and without modifying the 3G28 InGaP/InGaAs/Ge epitaxial cell structure, the appearance of the flat spot effect at LILT conditions can be practically eliminated. Analysis of the temperature behaviour of the fill factor of solar cells with optimized design show that in absence of the flat spot effect, the electrical performance of solar cells at LILT conditions is nevertheless mostly limited by tunnelling assisted current flow. For these solar cells, an average fill factor above 0.9 and an average efficiency higher than 33.5 % (at 0.037xAM0 and -120°C) are demonstrated.

  17. Influence of the Mendocino Triple Junction on the Tectonics of Coastal California

    NASA Astrophysics Data System (ADS)

    Furlong, Kevin P.

    2004-05-01

    The migration of the Mendocino triple junction through central and northern California over the past 2530 million years has led to a profound change in plate interactions along coastal California. The tectonic consequences of the abrupt change from subduction plate interactions north of the triple junction to the development of the San Andreas transform system south of the triple junction can be seen in the geologic record and geophysical observations. The primary driver of this tectonism is a coupling among the subducting Juan de Fuca (Gorda), North American, and Pacific plates that migrates with the triple junction. This coupling leads to ephemeral thickening of the overlying North American crust, associated uplift and subsequent subsidence, and a distinctive sequence of fault development and volcanism.

  18. Hydrothermal plumes at the Rodriguez triple junction, Indian ridge

    NASA Astrophysics Data System (ADS)

    Gamo, Toshitaka; Nakayama, Eiichiro; Shitashima, Kiminori; Isshiki, Kenji; Obata, Hajime; Okamura, Kei; Kanayama, Shinji; Oomori, Tamotsu; Koizumi, Takayuki; Matsumoto, Satoshi; Hasumoto, Hiroshi

    1996-07-01

    Water column anomalies of light transmission, Mn, Fe, Al and CH 4 concentrations were searched in the central, southeastern and southwestern Indian Ridge segments centered on the Rodriguez Triple Junction (RTJ) (˜25°32'S, ˜70°02'E), for the purpose of locating hydrothermally active areas, in July to August 1993. We found an active zone in the central Indian Ridge segment (25°18-20'S) approximately 12 miles north of the RTJ, where significant hydrothermal plumes were observed at 2,200-2,400 m depth. Intensive tow-yo observations using a CTD rosette multi-sampling system equipped with a transmissometer revealed that the plumes show temporal as well as spatial variations. Discrete water samples within the plumes were enriched in Mn, Fe, and CH 4, with maximum concentrations of 9.8 n M, 40.2 n M and 3.3 n M, respectively. Judging from the spatial and chemical characteristics of the plumes, especially from transmission anomalies and C/H 4Mn ratios, we speculate that the hydrothermal venting site might be not in the rift valley but on the eastern off-axis zone, several miles distant from the rift valley.

  19. Crustal velocity structure north of the Mendocino triple junction

    NASA Astrophysics Data System (ADS)

    Beaudoin, Bruce C.; Magee, Marian; Benz, Harley

    1994-10-01

    A 140-km-long refraction/wide-angle reflection profile recently recorded by Stanford University and the U.S. Geological Survey imaged the subducting Gorda slab beneath northern California. The profile, which is subparallel to the coast from Cape Mendocino northward, indicates that the North American plate is 13- to 14-km-thick along the coast north of Cape Mendocino. The crust is characterized by relatively uniform, low velocities of less than or = 6 km/s interpreted as Franciscan rocks. Two strong reflections define the upper and lower boundaries of the subducting Gorda crust. Our data indicate that the subducting Gorda crust thickens northward from Cape Mendocino from 7-km-thick just north of Cape Mendocino to 10-km-thick 120 km to the north. This change in thickness is coincident with a change in velocity from 6.7 km/s south to 6.2 km/s north. Mantle velocities of 7.7 km/s are observed for offsets greater than c. 80 km. We interpret our model to indicate that the Gorda slab is not imbricated on a crustal scale beneath our profile, that sediments and/or a tectonically thickened oceanic layer 2 are present to the north but not in the vicinity of Cape Mendocino, and that proximity to the Mendocino triple junction affects the way sediments are subducted.

  20. Transition from slab to slabless: Results from the 1993 Mendocino triple junction seismic experiment

    USGS Publications Warehouse

    Beaudoin, B.C.; Godfrey, N.J.; Klemperer, S.L.; Lendl, C.; Trehu, A.M.; Henstock, T.J.; Levander, A.; Holl, J.E.; Meltzer, A.S.; Luetgert, J.H.; Mooney, W.D.

    1996-01-01

    Three seismic refraction-reflection profiles, part of the Mendocino triple junction seismic experiment, allow us to compare and contrast crust and upper mantle of the North American margin before and after it is modified by passage of the Mendocino triple junction. Upper crustal velocity models reveal an asymmetric Great Valley basin overlying Sierran or ophiolitic rocks at the latitude of Fort Bragg, California, and overlying Sierran or Klamath rocks near Redding, California. In addition, the upper crustal velocity structure indicates that Franciscan rocks underlie the Klamath terrane east of Eureka, California. The Franciscan complex is, on average, laterally homogeneous and is thickest in the triple junction region. North of the triple junction, the Gorda slab can be traced 150 km inboard from the Cascadia subduction zone. South of the triple junction, strong precritical reflections indicate partial melt and/or metamorphic fluids at the base of the crust or in the upper mantle. Breaks in these reflections are correlated with the Maacama and Bartlett Springs faults, suggesting that these faults extend at least to the mantle. We interpret our data to indicate tectonic thickening of the Franciscan complex in response to passage of the Mendocino triple junction and an associated thinning of these rocks south of the triple junction due to assimilation into melt triggered by upwelling asthenosphere. The region of thickened Franciscan complex overlies a zone of increased scattering, intrinsic attenuation, or both, resulting from mechanical mixing of lithologies and/or partial melt beneath the onshore projection of the Mendocino fracture zone. Our data reveal that we have crossed the southern edge of the Gorda slab and that this edge and/or the overlying North American crust may have fragmented because of the change in stress presented by the edge.

  1. Research on stable, high-efficiency amorphous silicon multijunction modules. Annual subcontract report, 1 January 1991--31 December 1991

    SciTech Connect

    Banerjee, A.; Chen, E.; Clough, R.; Glatfelter, T.; Guha, S.; Hammond, G.; Hopson, M.; Jackett, N.; Lycette, M.; Noch, J.; Palmer, T.; Pawlikiewicz, A.; Rosenstein, I.; Ross, R.; Wolf, D.; Xu, X.; Yang, J.; Younan, K.

    1992-04-01

    This report describes the progress made during Phase 1 of research and development program to obtain high-efficiency amorphous silicon alloy multijunction modules. Using a large-area deposition system, double-and triple-junction cells were made on stainless steel substrates of over 1 ft{sup 2} area with Ag and ZnO predeposited back reflector. Modules of over 1 ft{sup 2} were produced with between 9.2% and 9.9 initial aperture-area efficiencies as measured under a USSC Spire solar simulator. Efficiencies as measured under the NREL Spire solar simulator were found to be typically 15% to 18% lower. The causes for this discrepancy are now being investigated. The modules show about 15% degradation after 600 hours of one-sun illumination at 50{degrees}C. To optimize devices for higher stabilized efficiency, a new method was developed by which the performance of single-junction cells after long-term, one-sun exposure at 50{degrees}C can be predicted by exposing cells to short-term intense light at different temperatures. This method is being used to optimize the component cells of the multijunction structure to obtain the highest light-degraded efficiency.

  2. Can plasmonic Al nanoparticles improve absorption in triple junction solar cells?

    NASA Astrophysics Data System (ADS)

    Yang, L.; Pillai, S.; Green, M. A.

    2015-07-01

    Plasmonic nanoparticles located on the illuminated surface of a solar cell can perform the function of an antireflection layer, as well as a scattering layer, facilitating light-trapping. Al nanoparticles have recently been proposed to aid photocurrent enhancements in GaAs photodiodes in the wavelength region of 400-900 nm by mitigating any parasitic absorption losses. Because this spectral region corresponds to the top and middle sub-cell of a typical GaInP/GaInAs/Ge triple junction solar cell, in this work, we investigated the potential of similar periodic Al nanoparticles placed on top of a thin SiO2 spacer layer that can also serve as an antireflection coating at larger thicknesses. The particle period, diameter and the thickness of the oxide layers were optimised for the sub-cells using simulations to achieve the lowest reflection and maximum external quantum efficiencies. Our results highlight the importance of proper reference comparison, and unlike previously published results, raise doubts regarding the effectiveness of Al plasmonic nanoparticles as a suitable front-side scattering medium for broadband efficiency enhancements when compared to standard single-layer antireflection coatings. However, by embedding the nanoparticles within the dielectric layer, they have the potential to perform better than an antireflection layer and provide enhanced response from both the sub-cells.

  3. Can plasmonic Al nanoparticles improve absorption in triple junction solar cells?

    PubMed Central

    Yang, L.; Pillai, S.; Green, M. A.

    2015-01-01

    Plasmonic nanoparticles located on the illuminated surface of a solar cell can perform the function of an antireflection layer, as well as a scattering layer, facilitating light-trapping. Al nanoparticles have recently been proposed to aid photocurrent enhancements in GaAs photodiodes in the wavelength region of 400–900 nm by mitigating any parasitic absorption losses. Because this spectral region corresponds to the top and middle sub-cell of a typical GaInP/GaInAs/Ge triple junction solar cell, in this work, we investigated the potential of similar periodic Al nanoparticles placed on top of a thin SiO2 spacer layer that can also serve as an antireflection coating at larger thicknesses. The particle period, diameter and the thickness of the oxide layers were optimised for the sub-cells using simulations to achieve the lowest reflection and maximum external quantum efficiencies. Our results highlight the importance of proper reference comparison, and unlike previously published results, raise doubts regarding the effectiveness of Al plasmonic nanoparticles as a suitable front-side scattering medium for broadband efficiency enhancements when compared to standard single-layer antireflection coatings. However, by embedding the nanoparticles within the dielectric layer, they have the potential to perform better than an antireflection layer and provide enhanced response from both the sub-cells. PMID:26138405

  4. Preliminary Low Temperature Electron Irradiation of Triple Junction Solar Cells

    NASA Technical Reports Server (NTRS)

    Stella, Paul M.; Mueller, Robert L.; Scrivner, Roy L.; Helizon, Roger S.

    2007-01-01

    For many years extending solar power missions far from the sun has been a challenge not only due to the rapid falloff in solar intensity (intensity varies as inverse square of solar distance) but also because some of the solar cells in an array may exhibit a LILT (low intensity low temperature) degradation that reduces array performance. Recent LILT tests performed on commercial triple junction solar cells have shown that high performance can be obtained at solar distances as great as approx. 5 AU1. As a result, their use for missions going far from the sun has become very attractive. One additional question that remains is whether the radiation damage experienced by solar cells under low temperature conditions will be more severe than when measured during room temperature radiation tests where thermal annealing may take place. This is especially pertinent to missions such as the New Frontiers mission Juno, which will experience cell irradiation from the trapped electron environment at Jupiter. Recent testing2 has shown that low temperature proton irradiation (10 MeV) produces cell degradation results similar to room temperature irradiations and that thermal annealing does not play a factor. Although it is suggestive to propose the same would be observed for low temperature electron irradiations, this has not been verified. JPL has routinely performed radiation testing on commercial solar cells and has also performed LILT testing to characterize cell performance under far sun operating conditions. This research activity was intended to combine the features of both capabilities to investigate the possibility of any room temperature annealing that might influence the measured radiation damage. Although it was not possible to maintain the test cells at a constant low temperature between irradiation and electrical measurements, it was possible to obtain measurements with the cell temperature kept well below room temperature. A fluence of 1E15 1MeV electrons was

  5. Self-powered and broadband photodetectors based on graphene/ZnO/silicon triple junctions

    NASA Astrophysics Data System (ADS)

    Cheng, Ching-Cheng; Zhan, Jun-Yu; Liao, Yu-Ming; Lin, Tai-Yuan; Hsieh, Ya-Ping; Chen, Yang-Fang

    2016-08-01

    A self-powered photodetector with ultrahigh sensitivity, fast photoresponse, and wide spectral detectivity covering from 1000 nm to 400 nm based on graphene/ZnO/Si triple junctions has been designed, fabricated, and demonstrated. In this device, graphene serves as a transparent electrode as well as an efficient collection layer for photogenerated carriers due to its excellent tunability of Fermi energy. The ZnO layer acts as an antireflection layer to trap the incident light and enhance the light absorption. Furthermore, the insertion of the ZnO layer in between graphene and Si layers can create build-in electric field at both graphene/ZnO and ZnO/Si interfaces, which can greatly enhance the charge separation of photogenerated electron and hole pairs. As a result, the sensitivity and response time can be significantly improved. It is believed that our methodology for achieving a high-performance self-powered photodetector based on an appropriate design of band alignment and optical parameters can be implemented to many other material systems, which can be used to generate unique optoelectronic devices for practical applications.

  6. Two-axis tracking, triple-junction PV concentrator based on water flotation

    NASA Astrophysics Data System (ADS)

    Parkyn, Bill

    2005-08-01

    Concentrating photovoltaics have the greatest performance for high solar efficiency, but current designs feature large high-profile tracking platforms that are expensive and laborious to install and maintain, and are vulnerable to even moderate winds. Moreover, their air cooling can only handle relatively low concentrations, and then only at elevated temperatures that can only shorten operating life. A previously described new approach has been implemented in a prototype that has been operating since last winter. This is an array of 450X concentrator utilizing 15mm-square water-cooled triple-junction cells, in lensed troughs that utilize flotation both for structural support and azimuth tracking. The troughs tilt as low as 24° solar altitude, for elevation tracking. The troughs float in only 14" of water, in circular ponds that can be close packed to cover 70% of the land with lenses, one-two orders of magnitude more effective land coverage than conventional concentrating systems, needing only two square miles per peak GigaWatt. The sealed troughs are mass-produced off-site and quickly installed by a small crew without any cranes or heavy machinery. Current costs are already under $2/Watt, and should drop in half for large-scale city-powering applications. The lens and auxiliary optics are discussed, and the water cell-cooling system is thermally analyzed.

  7. Temperature Characteristics Analysis of Triple-Junction Solar Cell under Concentrated Conditions using Spice Diode Model

    NASA Astrophysics Data System (ADS)

    Sakurada, Yuya; Ota, Yasuyuki; Nishioka, Kensuke

    2011-12-01

    Using spice diode model, the temperature characteristics of an InGaP/InGaAs/Ge triple-junction solar cell under concentrated light conditions were analyzed in detail. The current-voltage (I-V) characteristics of the single-junction solar cells (InGaP, InGaAs, and Ge solar cells) were measured at various temperatures. From dark I-V characteristics of each single-junction solar cell, the diode parameters and temperature exponents were extracted. The extracted diode parameters and temperature exponents were applied to the equivalent circuit model for the triple-junction solar cell, and the solar cell performance was calculated with considering the temperature characteristics of series resistance. There was good agreement between the measured and calculated I-V characteristics of the triple-junction solar cell at various temperatures under concentrated light conditions.

  8. Distributed deformation ahead of the Cocos-Nazca Rift at the Galapagos triple junction

    NASA Astrophysics Data System (ADS)

    Smith, Deborah K.; Schouten, Hans; Zhu, Wen-lu; Montési, Laurent G. J.; Cann, Johnson R.

    2011-11-01

    The Galapagos triple junction is not a simple ridge-ridge-ridge (RRR) triple junction. The Cocos-Nazca Rift (C-N Rift) tip does not meet the East Pacific Rise (EPR). Instead, two secondary rifts form the link: Incipient Rift at 2°40‧N and Dietz Deep volcanic ridge, the southern boundary of the Galapagos microplate (GMP), at 1°10‧N. Recently collected bathymetry data are used to investigate the regional tectonics prior to the establishment of the GMP (∼1.5 Ma). South of C-N Rift a band of northeast-trending cracks cuts EPR-generated abyssal hills. It is a mirror image of a band of cracks previously identified north of C-N Rift on the same age crust. In both areas, the western ends of the cracks terminate against intact abyssal hills suggesting that each crack initiated at the EPR spreading center and cut eastward into pre-existing topography. Each crack formed a short-lived triple junction until it was abandoned and a new crack and triple junction initiated nearby. Between 2.5 and 1.5 Ma, the pattern of cracking is remarkably symmetric about C-N Rift providing support for a crack interaction model in which crack initiation at the EPR axis is controlled by stresses associated with the tip of the westward-propagating C-N Rift. The model also shows that offsets of the EPR axis may explain times when cracking is not symmetric. South of C-N Rift, cracks are observed on seafloor as old as 10.5 Ma suggesting that this triple junction has not been a simple RRR triple junction during that time.

  9. In Situ Irradiation and Measurement of Triple Junction Solar Cells at Low Intensity, Low Temperature (LILT) Conditions

    NASA Technical Reports Server (NTRS)

    Harris, R.D.; Imaizumi, M.; Walters, R.J.; Lorentzen, J.R.; Messenger, S.R.; Tischler, J.G.; Ohshima, T.; Sato, S.; Sharps, P.R.; Fatemi, N.S.

    2008-01-01

    The performance of triple junction InGaP/(In)GaAs/Ge space solar cells was studied following high energy electron irradiation at low temperature. Cell characterization was carried out in situ at the irradiation temperature while using low intensity illumination, and, as such, these conditions reflect those found for deep space, solar powered missions that are far from the sun. Cell characterization consisted of I-V measurements and quantum efficiency measurements. The low temperature irradiations caused substantial degradation that differs in some ways from that seen after room temperature irradiations. The short circuit current degrades more at low temperature while the open circuit voltage degrades more at room temperature. A room temperature anneal after the low temperature irradiation produced a substantial recovery in the degradation. Following irradiation at both temperatures and an extended room temperature anneal, quantum efficiency measurement suggests that the bulk of the remaining damage is in the (In)GaAs sub-cell

  10. Simulation of the Mars surface solar spectra for optimized performance of triple junction solar cells

    NASA Technical Reports Server (NTRS)

    Edmondson, Kenneth M.; Joslin, David E.; Fetzer, Chris M.; King, Richard R.; Karam, Nasser H.; Mardesich, Nick; Stella, Paul M.; Rapp, Donald; Mueller, Robert

    2005-01-01

    The unparalleled success of the Mars Exploration Rovers (MER) powered by GaInP/GaAs/Ge triple-junction solar cells has demonstrated a lifetime for the rovers that exceeded the baseline mission duration by more than a factor of five.

  11. The Afar triple junction accommodation zone from InSAR derived strain and seismicity

    NASA Astrophysics Data System (ADS)

    Pagli, C.; Ebinger, C. J.; Keir, D.; Wang, H.

    2015-12-01

    Strain and seismicity show us the mode by which deformation is accommodated in rifting continents. Here we present a combined analysis of InSAR derived strain maps and seismicity of the Afar triple junction from 2006 to 2010. Our analysis shows that that the plate spreading motion is accommodated in different modes. A dogbone-shaped seismicity and strain distribution dominates the northern Red Sea branch of the triple junction, likely as a result of repeated dike intrusions 2005-2010. East of the triple junction, in the Gulf of Aden branch the strain and seismicity distribution appears decoupled. The strain focuses across the central part of several overlapping rifts, while the seismicity mainly occurs at the rift tips. Conversely, the Main Ethiopian Rift branch shows a narrow and elongated zone of both high strain and seismicity. The pattern suggests that the recent history of magmatic intrusions in the northern branch and mainly tectonic extension in the other branches creates a diverse triple junction accommodation zone.

  12. Fluids in the lower crust following Mendocino triple junction migration: Active basaltic intrusion?

    NASA Astrophysics Data System (ADS)

    Levander, Alan; Henstock, Timothy J.; Meltzer, Anne S.; Beaudoin, Bruce C.; Trehu, Anne M.; Klemperer, Simon L.

    1998-02-01

    Geodynamic and plate tectonic models for the Mendocino triple junction, a fault-fault-trench triple junction in northwestern California, predict a slab-free zone south of the triple junction in which asthenospheric mantle upwells to the base of the crust. A variety of geological and geophysical data support this model, although fine-scale (<20 km) details of the lithospheric structure have been unknown previously. Seismic investigations in the onshore transform regime south of the Mendocino triple junction region reveal very strong short-offset reflections from the lower crust and at the crust-mantle boundary beneath the entire width of the Coast Range, particularly near Lake Pillsbury, California. Seismic analysis suggests that these reflections are from discrete zones of fluid. The reflector geometry implies that the source of the fluid is within the upper mantle. In this tectonic context it is likely that the fluids are largely partial melt, segregated from asthenospheric mantle upwelling into the slab-free zone. The tectonic setting and the location of Lake Pillsbury relative to the estimated position of the southern edge of the Gorda slab and the Clear Lake volcanic field suggest that volcanism may initiate in this region within the next 400 k.y.

  13. Progress in amorphous silicon PV technology: An update

    SciTech Connect

    Luft, W.; Branz, H.M.; Dalal, V.L.; Hegedus, S.S.; Schiff, E.A.

    1995-07-01

    To reach the 15% stabilized efficiency goal for amorphous silicon (a-Si) modules by the year 2005, the National Renewable Energy Laboratory has established four research teams. The teams -- with members from industry, universities, and NREL -- have been in operation for 2.5 years now. Consensus has been reached that a triple-junction a-Si structure is needed to reach the efficiency goal. Performance parameter goals for the overall structure and the three component cells have been formulated. All four teams have generated their own development plans. Individual team progress relative to the plans is reported.

  14. Forearc Deformation, Arc Volcanism, and Landscape Evolution near the Cocos-Nazca-Caribbean Triple Junction

    NASA Astrophysics Data System (ADS)

    Morell, K. D.; Fisher, D.; Gardner, T.; Protti, M.

    2005-12-01

    New geologic mapping in SE Costa Rica and SW Panama reveals a system of structures and landscape features that are actively propagating with the Cocos-Nazca-Caribbean Triple Junction. The triple junction migrates to the SE at ~50 km/my, so the upper plate inboard of the Nazca plate experiences a rapid change from steep, slow subduction of the Nazca plate to shallow, rapid subduction of the Cocos plate. High plate boundary coupling for ~100 km NW of the triple junction has led to the development of the Fila Costena Thrust Belt. Balanced cross-sections indicate that shortening rates are highest near the center of the thrust belt, and decrease to the SE nearest the triple junction, where the thrust belt abruptly terminates. Right lateral tear faults cut the thrusts of the Fila Costena and allow for a sharp gradient in upper plate shortening above the subducted projection of the Panama Fracture Zone (PFZ), or the Cocos-Nazca boundary. East of the triple junction, a ridge exposes a fault-related anticline that may represent the incipient propagation of the Fila Costena into Panama. The volcanic arc is active just to the east of the onland projection of the subducting PFZ (e.g., Volcan Baru), with the extinct Talamanca arc lying to the west of this projection. Lahar fans on the slopes of the active Volcan Baru are analogous to the backtilted lahars now restricted to the rear of the Fila Costena. The spatial and temporal distribution of arc volcanism is consistent with a mantle wedge restricted to the east of the PFZ that migrates eastward with the triple junction. The Rio Chiriqui drainage system is currently the only river that carries arc volcanics to the eastern thrust front. The river skirts the southeast edge of the thrust belt and is inset into lahar fans on the slopes of Volcan Baru. Uplifted Quaternary fluvial terraces, located several kilometers west from the current drainage system, are offset at the thrust front by about 100-150 m. Andesite clasts in these

  15. Migration of grain boundaries and triple junctions in high-purity aluminum during annealing after slight cold rolling

    SciTech Connect

    Yin, Wenhong; Wang, Weiguo; Fang, Xiaoying; Qin, Congxiang; Xing, Xiaoguang

    2015-09-15

    Grain orientations and grain boundary migrations near triple junctions in a high purity aluminum were analyzed by electron back scattered diffraction. The results indicate that there are good correlations between the Schmid factors or Taylor factors and the misorientation values of point to original point in grains near the triple junctions in a slightly deformed sample. Grains with higher Schmid factors or lower Taylor factors typically correspond to higher misorientation values near the triple junctions. In a subsequent annealing at 400 °C, both grain boundaries and triple junctions migrate, but the former leave ghost lines. During such migration, a grain boundary grows from the grain with lower Schmid factor (higher Taylor factor) into the grain with higher Schmid factor (lower Taylor factor). Usually, the amount of migration of a grain boundary is considerably greater than that of a triple junction, and the grain boundary becomes more curved after migration. These observations indicate that the triple junctions have drag effects on grain boundary migration. - Highlights: • Polycrystalline aluminum with fine grains about 30 μm were used. • Off-line in situ EBSD was used to identify TJs before and after annealing. • Grains with higher SFs have higher misorientation values near TJs after deformation. • Grain boundaries grow from hard grains into soft grains during annealing. • Triple junctions have drag effects on grain boundaries migration.

  16. Research on stable, high-efficiency, amorphous silicon multijunction modules. Annual subcontract report, 1 May 1991--30 April 1992

    SciTech Connect

    Catalano, A.; Bennett, M.; Chen, L.; D`Aiello, R.; Fieselmann, B.; Li, Y.; Newton, J.; Podlesny, R.; Yang, L.

    1992-08-01

    This report describes work to demonstrate a multijunction module with a ``stabilized`` efficiency (600 h, 50{degrees}C, AM1.5) of 10.5%. Triple-junction devices and modules using a-Si:H alloys with carbon and germanium were developed to meet program goals. ZnO was used to provide a high optical transmission front contact. Proof of concept was obtained for several important advances deemed to be important for obtaining high (12.5%) stabilized efficiency. They were (1) stable, high-quality a-SiC:H devices and (2) high-transmission, textured ZnO. Although these developments were not scaled up and included in modules, triple-junction module efficiencies as high as 10.85% were demonstrated. NREL measured 9.62% and 9.00% indoors and outdoors, respectively. The modules are expected to lose no more than 20% of their initial performance. 28 refs.

  17. The Cape Mendocino, California, earthquakes of April 1992: Subduction at the triple junction

    USGS Publications Warehouse

    Oppenheimer, D.; Beroza, G.; Carver, G.; Dengler, L.; Eaton, J.; Gee, L.; Gonzalez, F.; Jayko, A.; Li, W.H.; Lisowski, M.; Magee, M.; Marshall, G.; Murray, M.; McPherson, R.; Romanowicz, B.; Satake, K.; Simpson, R.; Somerville, P.; Stein, R.; Valentine, D.

    1993-01-01

    The 25 April 1992 magnitude 7.1 Cape Mendocino thrust earthquake demonstrated that the North America-Gorda plate boundary is seismogenic and illustrated hazards that could result from much larger earthquakes forecast for the Cascadia region. The shock occurred just north of the Mendocino Triple Junction and caused strong ground motion and moderate damage in the immediate area. Rupture initiated onshore at a depth of 10.5 kilometers and propagated up-dip and seaward. Slip on steep faults in the Gorda plate generated two magnitude 6.6 aftershocks on 26 April. The main shock did not produce surface rupture on land but caused coastal uplift and a tsunami. The emerging picture of seismicity and faulting at the triple junction suggests that the region is likely to continue experiencing significant seismicity.

  18. The cape mendocino, california, earthquakes of april 1992: subduction at the triple junction.

    PubMed

    Oppenheimer, D; Eaton, J; Jayko, A; Lisowski, M; Marshall, G; Murray, M; Simpson, R; Stein, R; Beroza, G; Magee, M; Carver, G; Dengler, L; McPherson, R; Gee, L; Romanowicz, B; Gonzalez, F; Li, W H; Satake, K; Somerville, P; Valentine, D

    1993-07-23

    The 25 April 1992 magnitude 7.1 Cape Mendocino thrust earthquake demonstrated that the North America-Gorda plate boundary is seismogenic and illustrated hazards that could result from much larger earthquakes forecast for the Cascadia region. The shock occurred just north of the Mendocino Triple Junction and caused strong ground motion and moderate damage in the immediate area. Rupture initiated onshore at a depth of 10.5 kilometers and propagated up-dip and seaward. Slip on steep faults in the Gorda plate generated two magnitude 6.6 aftershocks on 26 April. The main shock did not produce surface rupture on land but caused coastal uplift and a tsunami. The emerging picture of seismicity and faulting at the triple junction suggests that the region is likely to continue experiencing significant seismicity. PMID:17770022

  19. Pulling the rug out from under California: Seismic images of the Mendocino Triple Junction Region

    NASA Astrophysics Data System (ADS)

    Mendocino Working Group; Trehu, Anne M.

    The active tectonic regime of northwestern California changes abruptly from transform motion to subduction at the Mendocino Triple Junction. Northward migration of the triple junction has been a major factor in the tectonic history of the continental margin of California since the Oligocene and continues at present. Understanding the effects of triple junction migration on the structure of the crust and upper mantle in this region is therefore necessary for reconstructing the geologic evolution of the continental margin of California and accurately assessing seismic hazards associated with the San Andreas fault system and the Cascadia subduction zone. In 1993 and 1994 a network of large-aperture seismic profiles was collected to image the crustal and upper-mantle structure beneath northern California and the adjacent continental margin. The data include approximately 650 km of onshore seismic refraction/reflection data, 2000 km of off-shore multichannel seismic (MCS) reflection data, and simultaneous onshore and offshore recording of the MCS airgun source to yield large-aperture data. Scientists from more than 12 institutions were involved in data acquisition.

  20. Stabilization of electrocatalytic metal nanoparticles at metal-metal oxide-graphene triple junction points.

    PubMed

    Kou, Rong; Shao, Yuyan; Mei, Donghai; Nie, Zimin; Wang, Donghai; Wang, Chongmin; Viswanathan, Vilayanur V; Park, Sehkyu; Aksay, Ilhan A; Lin, Yuehe; Wang, Yong; Liu, Jun

    2011-03-01

    Carbon-supported precious metal catalysts are widely used in heterogeneous catalysis and electrocatalysis, and enhancement of catalyst dispersion and stability by controlling the interfacial structure is highly desired. Here we report a new method to deposit metal oxides and metal nanoparticles on graphene and form stable metal-metal oxide-graphene triple junctions for electrocatalysis applications. We first synthesize indium tin oxide (ITO) nanocrystals directly on functionalized graphene sheets, forming an ITO-graphene hybrid. Platinum nanoparticles are then deposited, forming a unique triple-junction structure (Pt-ITO-graphene). Our experimental work and periodic density functional theory (DFT) calculations show that the supported Pt nanoparticles are more stable at the Pt-ITO-graphene triple junctions. Furthermore, DFT calculations suggest that the defects and functional groups on graphene also play an important role in stabilizing the catalysts. These new catalyst materials were tested for oxygen reduction for potential applications in polymer electrolyte membrane fuel cells, and they exhibited greatly enhanced stability and activity. PMID:21302925

  1. Investigation of the radiation resistance of triple-junction a-Si:H alloy solar cells irradiated with 1.00 MeV protons

    NASA Technical Reports Server (NTRS)

    Lord, Kenneth R., II; Walters, Michael R.; Woodyard, James R.

    1993-01-01

    The effect of 1.00 MeV proton irradiation on hydrogenated amorphous silicon alloy triple-junction solar cells is reported for the first time. The cells were designed for radiation resistance studies and included 0.35 cm(sup 2) active areas on 1.0 by 2.0 cm(sup 2) glass superstrates. Three cells were irradiated through the bottom contact at each of six fluences between 5.10E12 and 1.46E15 cm(sup -2). The effect of the irradiations was determined with light current-voltage measurements. Proton irradiation degraded the cell power densities from 8.0 to 98 percent for the fluences investigated. Annealing irradiated cells at 200 C for two hours restored the power densities to better than 90 percent. The cells exhibited radiation resistances which are superior to cells reported in the literature for fluences less than 1E14 cm(sup -2).

  2. Development of 1.25 eV InGaAsN for triple junction solar cells

    SciTech Connect

    LI,N.Y.; SHARPS,P.R.; HILLS,J.S.; HOU,H.; CHANG,PING-CHIH; BACA,ALBERT G.

    2000-05-16

    Development of next generation high efficiency space monolithic multifunction solar cells will involve the development of new materials lattice matched to GaAs. One promising material is 1.05 eV InGaAsN, to be used in a four junction GaInP{sub 2}/GaAs/InGaAsN/Ge device. The AMO theoretical efficiency of such a device is 38--42%. Development of the 1.05 eV InGaAsN material for photovoltaic applications, however, has been difficult. Low electron mobilities and short minority carrier lifetimes have resulted in short minority carrier diffusion lengths. Increasing the nitrogen incorporation decreases the minority carrier lifetime. The authors are looking at a more modest proposal, developing 1.25 eV InGaAsN for a triple junction GaInP{sub 2}/InGaAsN/Ge device. The AMO theoretical efficiency of this device is 30--34%. Less nitrogen and indium are required to lower the bandgap to 1.25 eV and maintain the lattice matching to GaAs. Hence, development and optimization of the 1.25 eV material for photovoltaic devices should be easier than that for the 1.05 eV material.

  3. Evidence for the jumping of the Mendocino triple junction, northern California

    SciTech Connect

    Borg, L.E.; Ford, D.P.; La Tourrette, T.Z.; Sutherland, H.T.; Walsh, T.P.

    1985-01-01

    The authors predict that the Mendocino triple junction will jump from its present location to a more northerly position defined by the intersection of the Blanco fracture zone, the Hayward-Lake Mountain fault system, and the Gorda trench. A similar jump may have occurred in the mid-Miocene during the shift from the San Gregorio-Hosgri to the San Andreas fault. North of Hollister, California, a series of northwest trending faults, known as the Hayward-Lake Mountain fault system, branch from the San Andreas fault. This fault system better approximates the trace of the small circle that describes the transform motion between the North American and Pacific plates. Displacement and slip measurements indicate that this fault system is progressing northward and that transform motion is shifting from the San Andreas to the Hayward-Lake Mountain fault system. Deformation of the Gorda plate as a result of compression during subduction can be resolved by the connection of the emerging Hayward-Lake Mountain fault system and the Blanco fracture zone. The Humboldt block is defined by the San Andreas fault, the Hayward-Lake Mountain fault system and the Gorda trench. This block is being deformed as a result of transform motion on these two faults. Propagation of volcanics through Northern California shows a direct correlation with both the paleo-positions of the Mendocino triple junction and the paths of transform faults. Geometric constructions applied to the Mendocino triple junction reveal that it is unstable at its present position and that a more northward position represents a more stable configuration.

  4. Adaptive Phase-Field Modeling of Anisotropic Wetting with Line Tension at the Triple Junction.

    PubMed

    Yeh, S Y; Lan, C W

    2015-09-01

    Line tension could affect the contact angle at triple junction, especially in micro- to nanoscale wetting. We have developed an adaptive phase-field model to consider the line tension quantitatively. This model is coupled to the smoothed boundary method for treating the contact line with the solid phase, while the volume constraint is imposed. Our calculated contact angles are in good agreement with the modified Young's equation. Further examples are illustrated for the anisotropic wetting on hydrophilic/hydrophobic stripes and rectangular grooves. PMID:26274914

  5. Orientations of recrystallization nuclei developed in columnar-grained Ni at triple junctions

    NASA Astrophysics Data System (ADS)

    Xu, C. L.; Huang, S.; Zhang, Y. B.; Wu, G. L.; Liu, Q.; Jensen, D. Juul

    2015-04-01

    A high purity columnar grained nickel sample with a strong <001> fiber texture was cold rolled to 50% reduction in thickness, followed by annealing at different temperatures. Optical microscopy was used to depict the grain boundaries prior to annealing and to detect nuclei formed on grain boundaries after annealing. Electron backscatter diffraction was performed to characterize the orientations of the nuclei and the deformed grains. Hardness tests were conducted at deformed grains. The potentials of triple junctions as preferential nucleation sites, the influence of deformation differences between adjacent grains on nucleation and orientation relationships between nuclei and parent matrix are analyzed.

  6. Growth and Strain Evaluation of InGaP/InGaAs/Ge Triple-Junction Solar Cell Structures

    NASA Astrophysics Data System (ADS)

    Alhomoudi, Ibrahim A.

    2016-06-01

    Metalorganic chemical vapor deposition (MOCVD) has been used for development of photovoltaic (PV) structures that enable enhanced efficiency for triple-junction solar cell (TJSC) devices. The in-plane strain, lattice match, surface defects, surface morphology, compositional uniformity, threading dislocations (TDs), and depth profile of each layer of the TJSC structure have been examined. The heteroepitaxial layers were found to be near lattice matched to the substrate with excellent coherence between the layers. The analysis explained that the indium gallium phosphide (InGaP) and indium gallium arsenide (InGaAs) layers on germanium (Ge) substrate are a strained structure with purely tetragonal crystalline phase, which indicates that the TJSC structural layers could maintain high crystalline quality. The biaxial in-plane strain in each layer of the TJSC structure is compressive and varies in magnitude for each layer in the structure, being strongly influenced by the Ge substrate and the multiple epilayers of the PV structure. Transmission electron microscopy (TEM) results show no TDs observed over a region with area of 500 nm2, with surface defect density less than 1 × 108 cm-2. No evidence of stacking faults and no visible defects of antiphase domains (APDs) at interfaces were observed, indicating adequate nucleation of epitaxial layers on the substrate and on subsequent growth layers. Furthermore, secondary-ion mass spectrometry (SIMS) analysis showed no significant Ge diffusion from the substrate into the TJSC structure.

  7. Experimental simulation of the accommodation in general-type triple junctions during the deformation of tricrystals and nanocrystalline structures

    NASA Astrophysics Data System (ADS)

    Sisanbaev, A. V.; Demchenko, A. A.; Demchenko, M. V.

    2013-10-01

    The development of the accommodation processes in general-type triple junctions is studied during the deformation of tricrystals and a system of nanocrystals with various grain sizes. Molecular dynamics simulation of the deformation of a system of nanocrystals with a grain size of ˜100 nm results in a set of accommodation processes that is identical to that in the tricrystals, namely, the nucleation of a dislocation "fold" at grain-boundary kinks and in triple junctions, the formation of subgrains near grain boundaries, grain fragmentation, and propeller-like grain-boundary migration near triple junctions. The appearance of nanograin rotation in a system of nanograins with a grain size of ˜10 nm is shown.

  8. Qualification of European Triple-Junction Solar Cells with Astrium PVA Technology

    NASA Astrophysics Data System (ADS)

    Dettlaff, K.; Gerhard, A.; Paaramann, C.; Bals, A.; Zimmermann, W.; Fernandez, E.; Caon, A.

    2008-09-01

    During the last couple of years the application of triple junction GaInP/GaInAs/Ge solar cells for all kind of missions - LEO, GEO, MEO and inter-planetary missions - came to pass, replacing the Si solar cells and related processing parameters.Comprehensive qualification programs have been performed at Astrium in order to qualify the new generations of solar cell types with Astrium's PVA technology. The actual generation of European triple junction GaInP/GaInAs/Ge solar cells manufactured by AZUR SPACE has been successfully qualified in the frame of the ESA ARTES3 programe for GEO-applications like Eurostar 3000 and Alpha-Bus and in the frame of GalileoSat for a MEO orbit. The delta qualification of the 3G28-ID2* solar cell and the associated PVA technology for LEO is currently running for the ESA SWARM project which will have operational temperatures up to 140°C in combination with an ATOX environment. The high operational temperature in combination with the high number of thermal cycles is a challenge for the solar cell interconnection technology and for the integral diode (ID2*). Different solar cell interconnector technologies have to be used and a protection against the ATOX environment has to be implemented. A further challenge of the SWARM project is the requirement for extremely high magnetic cleanliness.This paper will present qualification test results and the technical solutions to overcome the outlined challenges on PVA level.

  9. The Effects of MEO Radiation Environment on Triple-Junction GaAs Solar Cells

    NASA Astrophysics Data System (ADS)

    Xin, Gao; Sheng-sheng, Yang; Yun-fei, Wang; Zhan-zu, Feng

    The effects of MEO (Altitude 20,000 km, Inclination 56°) radiation environment on the degradation of triple-junction GaAs cells (Manufactured in China) are investigated to provide the reference for solar array design. The results are presented on the performance degradation of triple-junction GaAs cells with various thicknesses of shielding silica coverglass in the MEO radiation environment, using the displacement damage dose methodology for analyzing and modeling. Degradation at different electron energies has been correlated with displacement damage dose. The maximum power of the cells without coverglass will be seriously degraded, reducing it to below 20% of the initial value by the accumulating proton dose at the end of a 1-year-mission. However, using a 100-μm-thick coveglass, the maximum power of the cells can be maintanined at 90% of the initial value. While a 100-μm-thick silica coverglass can practically block off the effects of protons on the GaAs cells in the MEO environment, its effect is not so pronounced for electrons. The use of the coverglass is of vital importance for shielding the damages by low energy protons in the MEO orbit.

  10. Seismicity and Plate Geometry of the Mendocino Triple Junction Region, Northern California (1986-2006)

    NASA Astrophysics Data System (ADS)

    McPherson, B. C.; Pryor, I. S.; Williams, T. B.

    2007-12-01

    The Mendocino triple junction is an unstable triple junction located at the convergence of the North American (NAP), Pacific, and Gorda lithospheric plates near Cape Mendocino, northern California. Thirty years of seismic data (1976 - 2006) was analyzed to characterize plate geometry and stress orientations affecting the region. A simple 3-D model of plate geometry was developed to separate earthquake events occurring in the NAP or Gorda plate. Upper- hemisphere focal mechanism solutions were hand plotted for select earthquake events in the study area. NAP solutions north of the MTJ are primarily reverse mechanisms. P and T axes for these solutions indicate north-northeast (~N45E) directed pressure consistent with geodetic and geologic data. NAP solutions south of the MTJ are strike-slip solutions consistent with northwest striking faults of the northern San Andreas fault zone. Gorda plate solutions east of the MTJ are primarily normal fault solutions indicating downslab tension in the subducting plate. East-west cross section plots indicate a very dense cloud of seismicity at the MTJ and demonstrate a shallow dip angle (~8° - 12°) for the top of the Gorda plate to longitude 123.5 W. East of this longitude dip angle increases and Gorda plate seismicity phases out. North-south cross sections show a clear gap in seismicity coincident with an interpreted southern extent of the Gorda plate at latitude 40.25 N as well as the aseismic nature of both the Pacific plate and northern San Andreas fault proper.

  11. The state of stress near the Mendocino Triple Junction from inversion of earthquake focal mechanisms

    NASA Astrophysics Data System (ADS)

    Schwartz, Susan Y.; Hubert, Aurélia

    Focal mechanisms of 70 earthquakes occurring in the region of the Mendocino triple junction between 1977 and 1995 are inverted to obtain the regional stress orientations and relative magnitudes in this technically complex area. A diverse set of earthquake geometries is consistent with a single stress field characterized by north-northwest, horizontal, maximum principal compressive stress. Although this stress direction is almost perpendicular to convergence between the North American and Gorda plates, it is consistent with the stress direction inferred within the Gorda plate northwest of the triple junction. A maximum compressive stress direction nearly parallel to strike of the Cascadia subduction zone implies very low resolved shear stress across this plate boundary. Evidence for failure along the southernmost section of the Cascadia subduction zone comes from the occurrence of the recent 1992 (Ms=7.1) Cape Mendocino underthrusting earthquake as well as from measurements of Holocene surface uplift consistent with the 1992 coseismic uplift pattern. Rupture of the Cascadia subduction zone under this stress regime requires that the southernmost region of the Gorda-North American Plate boundary is weak.

  12. Crustal shear-wave splitting from local earthquakes in the Hengill triple junction, southwest Iceland

    USGS Publications Warehouse

    Evans, J.R.; Foulger, G.R.; Julian, B.R.; Miller, A.D.

    1996-01-01

    The Hengill region in SW Iceland is an unstable ridge-ridge-transform triple junction between an active and a waning segment of the mid-Atlantic spreading center and a transform that is transgressing southward. The triple junction contains active and extinct spreading segments and a widespread geothermal area. We evaluated shear-wave birefringence for locally recorded upper-crustal earthquakes using an array of 30 three-component digital seismographs. Fast-polarization directions, ??, are mostly NE to NNE, subparallel to the spreading axis and probably caused by fissures and microcracks related to spreading. However, there is significant variability in ?? throughout the array. The lag from fast to slow S is not proportional to earthquake depth (ray length), being scattered at all depths. The average wave-speed difference between qS1 and qS2 in the upper 2-5 km of the crust is 2-5%. Our results suggest considerable heterogeneity or strong S scattering.

  13. Formation and stability of ridge-ridge-ridge triple junctions in rheologically realistic lithosphere model

    NASA Astrophysics Data System (ADS)

    Gerya, Taras; Burov, Evgueni

    2015-04-01

    Triple junctions are probably the most remarkable features of plate boundaries since their presence constitutes one of the major demonstrations of plate tectonics theory. Divergent (R-R-R) triple junctions (at 120° and T junctions) are particular ones since their stability depends on the exact values of the relative velocities of plate divergence and hence is strongly affected by plate rheology and processes of crustal accretion. The mechanisms of their formation and long-term steadiness are not well understood even though it is commonly accepted, generally based on common sense, that the geometry and stability of triple junctions should be related to the intuitively acceptable geometric considerations that 3-branch configurations should be "stable" over the time on a 3D Earth surface. That said, most plate boundaries are in fact 2D in terms that they involve only two plates, while junctions with 3 and more branches, if even mechanically not excluded, are generally short-lived and hence rarely observed at tectonic scale. Indeed, it has been long-time suggested that triple junctions result from evolution of short-lived quadruple junctions, yet, without providing a consistent mechanical explanation or experimental demonstration of this process, due to the rheological complexity of the lithosphere and that of strain localization and crustal accretion processes. For example, it is supposed that R-R-R junctions form as result of axisymmetric mantle upwellings. However, impingement of buoyant fluid on a non-pre-stressed lithosphere should result in multiple radial cracks, as is well known from previous analog and numerical experiments. In case of uni-directionally pre-stressed lithosphere, it has also shown that linear 2D rift structures should be formed. Therefore, a complete 3D thermos-mechanically consistent approach is needed to understand the processes of formation of multi-branch junctions. With this goal we here reproduce and study the processes of multi

  14. Inverted GaInP/(In)GaAs/InGaAs Triple-Junction Solar Cells with Low-Stress Metamorphic Bottom Junctions: Preprint

    SciTech Connect

    Geisz, J. F.; Kurtz, S. R.; Wanlass, M. W.; Ward, J. S.; Duda, A.; Friedman, D. J.; Olson, J. M.; McMahon, W. E.; Moriarty, T. E.; Kiehl, J. T.; Romero, M. J.; Norman, A. G.; Jones, K. M.

    2008-05-01

    We demonstrate high efficiency performance in two ultra-thin, Ge-free III-V semiconductor triple-junction solar cell device designs grown in an inverted configuration. Low-stress metamorphic junctions were engineered to achieve excellent photovoltaic performance with less than 3 x 106 cm-2 threading dislocations. The first design with band gaps of 1.83/1.40/1.00 eV, containing a single metamorphic junction, achieved 33.8% and 39.2% efficiencies under the standard one-sun global spectrum and concentrated direct spectrum at 131 suns, respectively. The second design with band gaps of 1.83/1.34/0.89 eV, containing two metamorphic junctions achieved 33.2% and 40.1% efficiencies under the standard one-sun global spectrum and concentrated direct spectrum at 143 suns, respectively.

  15. Crustal Structure Near the Mendocino Triple Junction, California From Broadband Receiver Functions

    NASA Astrophysics Data System (ADS)

    Hall, C. E.; Schwartz, S. Y.; Sampson, D. E.; Furlong, K. P.

    2001-12-01

    We investigate crustal structure in the vicinity of the Mendocino triple junction (MTJ) to test the crustal conveyor model of crustal deformation (Furlong and Govers, 1999). This model predicts that the crust thickens in front of the triple junction and thins in its wake as the MTJ migrates to the northwest. Available seismic images of crustal structure in this region (tomography and reflection/refraction) indicate crustal thickness variations from less than 20 km north of the triple junction to as much as 35-40 km just to the south, thinning again further to the south. However, an improved delineation of crustal thickness and structure at specific locations is needed to constrain the tectonic evolution and geodynamics of the region. We deployed 2 broadband seismic stations (CVLO and FREY), that together with the Berkeley Digital Seismic Network station, HOPS, form a north-south transect in the region of large expected variations in crustal thickness and structure. Receiver function analysis on over 5 years of data from HOPS indicates a relatively thin (15 to 25 km) crust. The stacked receiver function for HOPS exhibits extremely large amplitude crustal multiples, which require a significant increase in density at the base of the crust. The crust beneath HOPS is successfully modeled as 15-18 km of low density Franciscan complex overlying a thin (5-10 km) underplated metamorphic (eclogitic) layer. This is consistent with the existence of a lower crustal mafic layer proposed by Hole, et al, 1998. Receiver function analysis on about one year of data from FREY and CVLO (about 40 and 80 km north of HOPS respectively) indicates that FREY has a similar crustal thickness to HOPS and CVLO has considerably thicker crust (30 to 40 km). This is consistent with predictions of the Mendocino crustal conveyor model. However, receiver functions from both FREY and CVLO exhibit azimuthal variations suggesting a dipping Moho or strong regional variations. These receiver functions do

  16. Triple junction magmatism: a geochemical study of Neogene volcanic rocks in western California

    USGS Publications Warehouse

    Johnson, C.M.; O'Neil, J.R.

    1984-01-01

    Inception of volcanism at late Oligocene to Recent centers in the eastern Coast Ranges of California (ECR suite) regularly decreases in age northward and is correlated with the northward migration of the transform-transform-trench Mendocino triple junction (MTJ). Miocene volcanism in the southern California basin (SCB suite) is spatially and temporally associated with the transform-ridge-trench Rivera triple junction (RTJ). The tholeiitic to calc-alkaline rocks in both suites were erupted through older trench melange while arc magmatism was occurring several hundred kilometers to the east. Therefore they are not related to subduction zone magmatism, but instead to interactions of the MTJ and RTJ with the continental margin. The ECR rocks, dominantly intermediate to silicic in composition, have relatively high ??18O values up to 11.3, 87Sr 86Sr ratios up to 0.7055, as well as relatively high Th contents, suggesting that crustal anatexis played a dominant role in their generation. Coupled crystal fractionation and crustal assimilation by an initially basaltic magma cannot explain the high ??18O values and 87Sr 86Sr ratios because greater than 95% of the basalt would need to crystallize. In contrast, the SCB rocks, dominantly mafic to intermediate in composition, have relatively low ??18O values down to 5.2 and 87Sr 86Sr ratios down to 0.7025 suggesting that these rocks were derived dominantly from a mantle source. Whether crustal anatexis occurs is determined largely by the type of stress a triple junction imposes upon the continental margin. Both the MTJ and RTJ are associated with high heat flow and magma fluxes from the mantle. The transform-transform-trench MTJ is associated with locally variable mild extension to compression and therefore allows pooling of basaltic magma in the crust to initiate crustal melting. The high rates of continental extension associated with the transform-ridge-trench RTJ prevents such pooling of magma. The space created by decoupling

  17. Tectonics and evolution of the Juan Fernandez microplate at the Pacific-Nazca-Antarctic triple junction

    NASA Technical Reports Server (NTRS)

    Anderson-Fontana, S.; Larson, R. L.; Engein, J. F.; Lundgren, P.; Stein, S.

    1986-01-01

    Magnetic and bathymetric profiles derived from the R/V Endeavor survey and focal mechanism studies for earthquakes on two of the Juan Fernandez microplate boundaries are analyzed. It is observed that the Nazca-Juan Fernandez pole is in the northern end of the microplate since the magnetic lineation along the East Ridge of the microplate fans to the south. The calculation of the relative motion of the Juan Fernandez-Pacific-Nazca-Antarctic four-plate system using the algorithm of Minster et al. (1974) is described. The development of tectonic and evolutionary models of the region is examined. The tectonic model reveals that the northern boundary of the Juan Fernandez microplate is a zone of compression and that the West Ridge and southwestern boundary are spreading obliquely; the evolutionary model relates the formation of the Juan Fernandez microplate to differential spreading rates at the triple junction.

  18. Seismicity and crustal structure at the Mendocino triple junction, Northern California

    SciTech Connect

    Dicke, M.

    1998-12-01

    A high level of seismicity at the Mendocino triple junction in Northern California reflects the complex active tectonics associated with the junction of the Pacific, North America, and Gorda plates. To investigate seismicity patterns and crustal structure, 6193 earthquakes recorded by the Northern California Seismic Network (NCSN) are relocated using a one-dimensional crustal velocity model. A near vertical truncation of the intense seismic activity offshore Cape Mendocino follows the strike of the Mattole Canyon fault and is interpreted to define the Pacific plate boundary. Seismicity along this boundary displays a double seismogenic layer that is attributed to interplate activity with the North America plate and Gorda plate. The interpretation of the shallow seismogenic zone as the North America - Pacific plate boundary implies that the Mendocino triple junction is situated offshore at present. Seismicity patterns and focal mechanisms for events located within the subducting Gorda pl ate are consistent with internal deformation on NE-SW and NW-SE trending rupture planes in response to north-south compression. Seismic sections indicate that the top of the Gorda plate locates at a depth of about 18 Km beneath Cape Mendocino and dips gently east-and southward. Earthquakes that are located in the Wadati-Benioff zone east of 236{sup o}E show a change to an extensional stress regime indicative of a slab pull force. This slab pull force and scattered seismicity within the contractional forearc region of the Cascadia subduction zone suggest that the subducting Gorda plate and the overriding North America plate are strongly coupled. The 1992 Cape Mendocino thrust earthquake is believed to have ruptured a blind thrust fault in the forearc region, suggesting that strain is accumulating that must ultimately be released in a potential M 8+ subduction earthquake.

  19. High Efficiency and High Rate Deposited Amorphous Silicon-Based Solar Cells: Final Technical Report, 1 September 2001--6 March 2005

    SciTech Connect

    Deng, X.

    2006-01-01

    The objectives for the University of Toledo are to: (1) establish a transferable knowledge and technology base for fabricating high-efficiency triple-junction a-Si-based solar cells, and (2) develop high-rate deposition techniques for the growing a-Si-based and related alloys, including poly-Si, c-Si, a-SiGe, and a-Si films and photovoltaic devices with these materials.

  20. Research on stable, high efficiency amorphous silicon multijunction modules. Semiannual technical progress report, 1 May 1991--31 October 1991

    SciTech Connect

    Catalano, A.; Arya, R.R.; Bennett, M.; Chen, L.; D`Aiello, R.; Fieselmann, B.; Li, Y.; Newton, J.; Podlesny, R.; Wiedeman, S.; Yang, L.

    1992-02-01

    Improvements towards a goal of a 12.5% initial triple-junction module efficiency require the use of a wide gap top-layer for improved open circuit voltage, higher transmission from the transparent front contact and more highly transmitting doped layers. To address the first issue, there has been continued development of a-SiC:H with the utilization of several novel feedstocks to control the atomic structure of the solid. These films have transport properties superior to the best results reported for a-SiC:H. Preliminary results with devices exhibits a stability comparable to a-Si:H, while previous results with a-SiC:H have generally shown for higher rates of degradation. Module fabrication has been refined to the extent that comparable module and small area device efficiencies are readily obtained. Despite the high initial efficiencies (9%--10%) obtained in 935 cm{sup 2} modules employing devices with 4000{Angstrom} thick middle junctions, higher than expected rates of degradation were found. The cause of the anomalous degradation was traced to shunts present in the device arising from defects in the tin oxide coating. NREL degradation results of triple-junction modules showed stabilized performance of the initial efficiency for modules prepared during the period in which shunts were a problem. 20 refs.

  1. Research on stable, high-efficiency amorphous silicon multijunction modules. Semiannual subcontract report, 1 January 1992--30 June 1992

    SciTech Connect

    Guha, S.

    1992-09-01

    This report describes research on semiconductor and non-semiconductor materials to enhance the performance of multi-band-gap, multijunction panel with an area greater than 900 cm{sup 2} by 1992. Double-junction and triple-junction cells are mode on a Ag/ZnO back reflector deposited on stainless steel substrates. An a-SiGe alloy is used for the i-layer in the bottom and the middle cells; the top cell uses an amorphous silicon alloy. After the evaporation of an antireflection coating, silver grids and bus bars are put on the top surface and the panel is encapsulated in an ethylene vinyl acetate (EVA)/Tefzel structure to make a 1-ft{sup 2} monolithic module.

  2. Transient cracks and triple junctions induced by Cocos-Nazca propagating rift

    NASA Astrophysics Data System (ADS)

    Schouten, H.; Smith, D. K.; Zhu, W.; Montesi, L. G.; Mitchell, G. A.; Cann, J. R.

    2009-12-01

    The Galapagos triple junction is a ridge-ridge-ridge triple junction where the Cocos, Nazca, and Pacific plates meet around the Galapagos microplate (GMP). On the Cocos plate, north of the large gore that marks the propagating Cocos-Nazca (C-N) Rift, a 250-km-long and 50-km-wide band of NW-SE-trending cracks crosscuts the N-S-trending abyssal hills of the East Pacific Rise (EPR). These appear as a succession of minor rifts, accommodating some NE-SW extension of EPR-generated seafloor. The rifts successively intersected the EPR in triple junctions at distances of 50-100 km north of the tip of the C-N Rift. We proposed a simple crack interaction model to explain the location of the transient rifts and their junction with the EPR. The model predicts that crack locations are controlled by the stress perturbation along the EPR, induced by the dominant C-N Rift, and scaled by the distance of its tip to the EPR (Schouten et al., 2008). The model also predicts that tensile stresses are symmetric about the C-N Rift and thus, similar cracks should have occurred south of the C-N Rift prior to formation of the GMP about 1 Ma. There were no data at the time to test this prediction. In early 2009 (AT 15-41), we mapped an area on the Nazca plate south of the C-N rift out to 4 Ma. The new bathymetric data confirm the existence of a distinctive pattern of cracks south of the southern C-N gore that mirrors the pattern on the Cocos plate until about 1 Ma, and lends support to the crack interaction model. The envelope of the symmetric cracking pattern indicates that the distance between the C-N Rift tip and the EPR varied between 40 and 65 km during this time (1-4 Ma). The breakdown of the symmetry at 1 Ma accurately dates the onset of a southern plate boundary of the GMP, now Dietz Deep Rift. At present, the southern rift boundary of the GMP joins the EPR with a steep-sided, 80 km long ridge. This ridge releases the stress perturbation otherwise induced along the EPR by elastic

  3. The Mendocino triple junction: Active faults, episodic coastal emergence, and rapid uplift

    NASA Astrophysics Data System (ADS)

    Merritts, Dorothy J.

    1996-03-01

    A complex zone of rapid Holocene surface uplift and deformation occurs at the Mendocino triple junction, the juncture of three plate-bounding faults: the Cascadia subduction zone, San Andreas fault, and Mendocino fault. Within this mountainous structural knot, up to 1.4 m of coastal emergence occurred during the 1992 Cape Mendocino MS 7.1 earthquake. Surveying and radiometric dating of ancient marine strandlines (<8000 years) along the trace of the southernmost Cascadia subduction zone indicate that the Holocene pattern of net surface uplift is very similar to the 1992 coseismic uplift pattern. Results of this investigation also indicate that episodic emergence occurred at least four times between about 600 and 7000 years ago and that some past events might have resulted in larger amounts of uplift (˜2.5 m) than the 1992 earthquake, perhaps during great earthquakes (M>7.5) along the Cascadia subduction zone megathrust. However, another plausible interpretation of the data is that multiple earthquakes resulting in smaller amounts of net surface uplift per event (similar to the 1992 earthquake) occurred closely spaced in time, giving the appearance in the geologic record of less frequent and larger events. Regardless of the number and timing of paleoearthquakes, the number of platforms is a minimum of the number of events that resulted in sudden, rapid uplift, because platform preservation is also a function of rising Holocene sea level. At present, rates and patterns of net surface uplift are better constrained than the timing and magnitude of paleoearthquakes. Periods of rapid Holocene emergence also are identified as far south of the area of 1992 uplift and the Mendocino fault as ˜30 km, along the unlocated San Andreas fault. These also might be associated with coseismic uplift. Based on new mapping of active faults in the region, it is proposed here that this uplift is the result of multiple discontinuous thrust and strike-slip fault segments which distribute

  4. Amorphous metal distribution transformers: The energy-efficient alternative

    SciTech Connect

    Garrity, T.F.

    1994-12-31

    Amorphous metal distribution transformers have been commercially available for the past 13 years. During that time, they have realized the promise of exceptionally high core efficiency as compared to silicon steel transformer cores. Utility planners today must consider all options available to meet the requirements of load growth. While additional generation capacity will be added, many demand-side initiatives are being undertaken as complementary programs to generation expansion. The efficiency improvement provided by amorphous metal distribution transformers deserves to be among the demand-side options. The key to understanding the positive impact of amorphous metal transformer efficiency is to consider the aggregate contribution those transformers can make towards demand reduction. It is estimated that distribution transformer core losses comprise at least 1% of the utility`s peak demand. Because core losses are continuous, any significant reduction in their magnitude is of great significance to the planner. This paper describes the system-wide economic contributions amorphous metal distribution transformers can make to a utility and suggests evaluation techniques that can be used. As a conservation tool, the amorphous metal transformer contributes to reduced power plant emissions. Calibration of those emissions reductions is also discussed in the paper.

  5. Detailed Analysis of Temperature Characteristics of an InGaP/InGaAs/Ge Triple-Junction Solar Cell

    NASA Astrophysics Data System (ADS)

    Nishioka, Kensuke; Sueto, Tsuyoshi; Uchida, Masaki; Ota, Yasuyuki

    2010-06-01

    Temperature characteristics of an InGaP/InGaAs/Ge triple-junction solar cell were analyzed in detail using an equivalent circuit calculation. The current-voltage ( I- V) characteristics of single-junction solar cells (InGaP, InGaAs, Ge solar cells) were measured at various temperatures. Fitting of I- V curves between measured and calculated data was carried out, and the diode parameters and temperature exponents of the single-junction solar cells were extracted. The parameters for each single-junction solar cell were used in the equivalent circuit model for the triple-junction solar cell, and calculations of solar cell performance were carried out. Measured and calculated results of the I- V characteristics at various temperatures agreed well.

  6. Large-area triple-junction a-Si alloy production scaleup. Annual subcontract report, 17 March 1993--18 March 1994

    SciTech Connect

    Oswald, R.; Morris, J.

    1994-11-01

    The objective of this subcontract over its three-year duration is to advance Solarex`s photovoltaic manufacturing technologies, reduce its a-Si:H module production costs, increase module performance and expand the Solarex commercial production capacity. Solarex shall meet these objectives by improving the deposition and quality of the transparent front contact, by optimizing the laser patterning process, scaling-up the semiconductor deposition process, improving the back contact deposition, scaling-up and improving the encapsulation and testing of its a-Si:H modules. In the Phase 2 portion of this subcontract, Solarex focused on improving deposition of the front contact, investigating alternate feed stocks for the front contact, maximizing throughput and area utilization for all laser scribes, optimizing a-Si:H deposition equipment to achieve uniform deposition over large-areas, optimizing the triple-junction module fabrication process, evaluating the materials to deposit the rear contact, and optimizing the combination of isolation scribe and encapsulant to pass the wet high potential test. Progress is reported on the following: Front contact development; Laser scribe process development; Amorphous silicon based semiconductor deposition; Rear contact deposition process; Frit/bus/wire/frame; Materials handling; and Environmental test, yield and performance analysis.

  7. Tension, cell shape and triple-junction angle anisotropy in the Drosophila germband

    NASA Astrophysics Data System (ADS)

    Lacy, Monica; Hutson, M. Shane; Meyer, Christian; McDonald, Xena

    In the field of tissue mechanics, the embryonic development of Drosophila melanogaster offers many opportunities for study. One of Drosophila's most crucial morphogenetic stages is the retraction of an epithelial tissue called the germband. During retraction, the segments of the retracting germband, as well as the individual germband cells, elongate in response to forces from a connected tissue, the amnioserosa. Modeling of this elongation, based on tissue responses to laser wounding, has plotted the internal germband tension against the external amnioserosa stress, creating a phase space to determine points and regions corresponding to stable elongation. Although the resulting fits indicate a necessary opposition of internal and external forces, they are inconclusive regarding the exact balance. We will present results testing the model predictions by measuring cell shapes and the correlations between cell-edge directions and triple-junction angles. These measures resolve the ambiguity in pinpointing the internal-external force balance for each germband segment. Research was supported by NIH Grant Numbers 1R01GM099107 and 1R21AR068933.

  8. Structural stability and energetics of grain boundary triple junctions in face centered cubic materials.

    PubMed

    Adlakha, I; Solanki, K N

    2015-01-01

    We present a systematic study to elucidate the role of triple junctions (TJs) and their constituent grain boundaries on the structural stability of nanocrystalline materials. Using atomistic simulations along with the nudge elastic band calculations, we explored the atomic structural and thermodynamic properties of TJs in three different fcc materials. We found that the magnitude of excess energy at a TJ was directly related to the atomic density of the metal. Further, the vacancy binding and migration energetics in the vicinity of the TJ were examined as they play a crucial role in the structural stability of NC materials. The resolved line tension which takes into account the stress buildup at the TJ was found to be a good measure in predicting the vacancy binding tendency near the TJ. The activation energy for vacancy migration along the TJ was directly correlated with the measured excess energy. Finally, we show that the resistance for vacancy diffusion increased for TJs with larger excess stored energy and the defect mobility at some TJs is slower than their constituent GBs. Hence, our results have general implications on the diffusional process in NC materials and provide new insight into stabilizing NC materials with tailored TJs. PMID:25732834

  9. Structural stability and energetics of grain boundary triple junctions in face centered cubic materials

    NASA Astrophysics Data System (ADS)

    Adlakha, I.; Solanki, K. N.

    2015-03-01

    We present a systematic study to elucidate the role of triple junctions (TJs) and their constituent grain boundaries on the structural stability of nanocrystalline materials. Using atomistic simulations along with the nudge elastic band calculations, we explored the atomic structural and thermodynamic properties of TJs in three different fcc materials. We found that the magnitude of excess energy at a TJ was directly related to the atomic density of the metal. Further, the vacancy binding and migration energetics in the vicinity of the TJ were examined as they play a crucial role in the structural stability of NC materials. The resolved line tension which takes into account the stress buildup at the TJ was found to be a good measure in predicting the vacancy binding tendency near the TJ. The activation energy for vacancy migration along the TJ was directly correlated with the measured excess energy. Finally, we show that the resistance for vacancy diffusion increased for TJs with larger excess stored energy and the defect mobility at some TJs is slower than their constituent GBs. Hence, our results have general implications on the diffusional process in NC materials and provide new insight into stabilizing NC materials with tailored TJs.

  10. The nature, distribution, and origin of gas hydrate in the Chile Triple Junction region

    USGS Publications Warehouse

    Brown, K.M.; Bangs, N.L.; Froelich, P.N.; Kvenvolden, K.A.

    1996-01-01

    A bottom simulating reflector (BSR) is regionally distributed throughout much of the Chile Triple Junction (CTJ) region. Downhole temperature and logging data collected during Ocean Drilling Program (ODP) Leg 141 suggest that the seismic BSR is generated by low seismic velocities associated with the presence of a few percent free gas in a ??? 10 m thick zone just beneath the hydrate-bearing zone. The data also indicate that the temperature and pressure at the BSR best corresponds to the seawater/methane hydrate stability field. The origin of the large amounts of methane required to generate the hydrates is, however, problematic. Low total organic carbon contents and low alkalinities argue against significant in situ biogenic methanogenesis, but additional input from thermogenic sources also appears to be precluded. Increasing thermal gradients, associated with the approach of the spreading ridge system, may have caused the base of the hydrate stability field to migrate 300 m upwards in the sediments. We propose that the upward migration of the base of the stability field has concentrated originally widely dispersed hydrate patches into the more continuous hydrate body we see today. The methane can be concentrated if the gas hydrates can form from dissolved methane, transported into the hydrate zone via diffusion or fluid advection. A strong gradient may exist in dissolved methane concentration across the BSR leading to the steady reabsorbtion of the free gas zone during the upward migration of the BSR even in the absence of fluid advection.

  11. High Current ESD Test of Advanced Triple Junction Solar Array Coupon

    NASA Technical Reports Server (NTRS)

    Wright, Kenneth H., Jr.; Schneider, Todd A.; Vaughn, Jason A.; Hoang, Bao; Wong, Frankie

    2014-01-01

    Testing was conducted on an Advanced Triple Junction (ATJ) coupon that was part of a risk reduction effort in the development of a high-powered solar array design by Space Systems Loral, LLC (SSL). The ATJ coupon was a small, 4-cell, two-string configuration of flight-type design that has served as the basic test coupon design used in previous SSL environmental aging campaigns. The objective of the present test was to evaluate the performance of the coupon after being subjected to induced electrostatic discharge (ESD) testing at two string voltages (100 V, 150 V) and four string currents (1.65 A, 2.0 A, 2.475 A, and 3.3 A). An ESD test circuit, unique to SSL solar array design, was built that simulates the effect of missing cells and strings in a full solar panel with special primary arc flashover circuitry. A total of 73 primary arcs were obtained that included 7 temporary sustained arcs (TSA) events. The durations of the TSAs ranged from 50 micro-seconds to 2.75 milli-seconds. All TSAs occurred at a string voltage of 150 V. Post-ESD functional testing showed that no degradation occurred due to the TSA events. These test results point to a robust design for application to a high-current, high-power mission.

  12. Structural stability and energetics of grain boundary triple junctions in face centered cubic materials

    PubMed Central

    Adlakha, I.; Solanki, K. N.

    2015-01-01

    We present a systematic study to elucidate the role of triple junctions (TJs) and their constituent grain boundaries on the structural stability of nanocrystalline materials. Using atomistic simulations along with the nudge elastic band calculations, we explored the atomic structural and thermodynamic properties of TJs in three different fcc materials. We found that the magnitude of excess energy at a TJ was directly related to the atomic density of the metal. Further, the vacancy binding and migration energetics in the vicinity of the TJ were examined as they play a crucial role in the structural stability of NC materials. The resolved line tension which takes into account the stress buildup at the TJ was found to be a good measure in predicting the vacancy binding tendency near the TJ. The activation energy for vacancy migration along the TJ was directly correlated with the measured excess energy. Finally, we show that the resistance for vacancy diffusion increased for TJs with larger excess stored energy and the defect mobility at some TJs is slower than their constituent GBs. Hence, our results have general implications on the diffusional process in NC materials and provide new insight into stabilizing NC materials with tailored TJs. PMID:25732834

  13. Three-dimensional thermal modeling for the Mendocino Triple Junction area

    NASA Astrophysics Data System (ADS)

    Goes, Saskia; Govers, Rob; Schwartz, Susan; Furlong, Kevin

    1997-04-01

    Complex interaction between the Pacific, North American, and Juan de Fuca plates at the northward migrating Mendocino Triple Junction (MTJ) has had a profound effect on the geological evolution of western North America. This paper presents a three-dimensional thermal model for the area around the MTJ that is based on its kinematic evolution, incorporating the effects of an asthenospheric slab window, changes in relative plate motions and the trenchward migration of the Juan de Fuca-Pacific spreading ridge. The thermal equation, including conductive and advective heat transport, is solved numerically using finite differences. Surface heat flow data and the trend in the maximum depth of seismicity south of the MTJ can be quite well explained by the thermal model. A finite lithospheric thickness above the slab window is required to fit heat flow measurements; however, the lack of data west of the San Andreas Fault prevents discriminating between underthrusting and accretionary mechanisms of lithospheric thickening. A comparison between the thermal and recent seismic velocity models reveals that P-wave anomalies in the uppermost mantle have smaller wavelengths and larger amplitudes than predicted if they were purely thermal.

  14. Interpreting Quaternary uplift rates at the Mendocino triple junction, northern California, from uplifted marine terraces

    SciTech Connect

    Merritts, D. ); Bull, W.B. )

    1989-11-01

    Analysis of the altitudinal spacing of 14 flights of marine terraces indicates a spatial pattern of varying uplift rates that agrees with that determined from previously dated terraces for the past 3-81 ka, and temporal changes in uplift rates from <1 m/ka to 3-5 m/ka that may reflect response to changes in tectonic regime during passage of the Mendocino triple junction (MTJ). A possible mechanism for regional uplift is growth of a slab window south of the MTJ. The region of most rapid uplift is 25-43 km south of the MTJ, immediately south of the northern boundary of the slab window. The coastline is tilted upward to the south in the region directly above the southern edge of the subducted Gorda plate. At Point Delgada, 55 km south of the present MTJ, where the northern edge of the slab window passes {approximately}300 ka, uplift rates have been 1.2 m/ka for at least 330 ka. More than 1.4 m.y. after passage of the southern edge of the subducted slab, at the Mendocino coast, uplift rates have been less than 0.4 m/ka for at least 330 ka.

  15. The Blow Up Method for Brakke Flows: Networks Near Triple Junctions

    NASA Astrophysics Data System (ADS)

    Tonegawa, Yoshihiro; Wickramasekera, Neshan

    2016-09-01

    We introduce a parabolic blow-up method to study the asymptotic behavior of a Brakke flow of planar networks (that is a 1-dimensional Brakke flow in a two dimensional region) weakly close in a space-time region to a static multiplicity 1 triple junction J. We show that such a network flow is regular in a smaller space-time region, in the sense that it consists of three curves coming smoothly together at a single point at 120{^{circ}} angles, staying smoothly close to J and moving smoothly. Using this result and White's stratification theorem, we deduce that whenever a Brakke flow of networks in a space-time region {{mathcal {R}}} has no static tangent flow with density {{≥q}2}, there exists a closed subset {{Σ subset {mathcal {R}}}} of parabolic Hausdorff dimension at most 1 such that the flow is classical in {{mathcal {R}}backslashΣ}, that is near every point in {{mathcal {R}}backslashΣ}, the flow, if non-empty, consists of either an embedded curve moving smoothly or three embedded curves meeting smoothly at a single point at 120{^{circ}} angles and moving smoothly. In particular, such a flow is classical at all times except for a closed set of times of ordinary Hausdorff dimension at most {1/2}.

  16. Amorphous and Nanocomposite Materials for Energy-Efficient Electric Motors

    NASA Astrophysics Data System (ADS)

    Silveyra, Josefina M.; Xu, Patricia; Keylin, Vladimir; DeGeorge, Vincent; Leary, Alex; McHenry, Michael E.

    2016-01-01

    We explore amorphous soft-magnetic alloys as candidates for electric motor applications. The Co-rich system combines the benefits of low hysteretic and eddy-current losses while exhibiting negligible magnetostriction and robust mechanical properties. The amorphous precursors can be devitrified to form nanocomposite magnets. The superior characteristics of these materials offer the advantages of ease of handling in the manufacturing processing and low iron losses during motor operation. Co-rich amorphous ribbons were laser-cut to build a stator for a small demonstrator permanent-magnet machine. The motor was tested up to ~30,000 rpm. Finite-element analyses proved that the iron losses of the Co-rich amorphous stator were ~80% smaller than for a Si steel stator in the same motor, at 18,000 rpm (equivalent to an electric frequency of 2.1 kHz). These low-loss soft magnets have great potential for application in highly efficient high-speed electric machines, leading to size reduction as well as reduction or replacement of rare earths in permanent-magnet motors. More studies evaluating further processing techniques for amorphous and nanocomposite materials are needed.

  17. Detailed Axial Morphology of the Chile Rise as it Approaches the Chile Triple Junction

    NASA Astrophysics Data System (ADS)

    Blackman, D. K.; Henig, A. S.; Barroso, E.; Grevemeyer, I.; Thurber, A. R.; German, C. R.; Inspire Cruise Participants, T.

    2010-12-01

    New bathymetric mapping along the two southernmost Chile Rise spreading segments shows axial volcanic structure that had not been evident in prior data. On the first segment extending north from the triple junction, where the basement is not obscured by sediment, a narrow line of volcanic structures appears to track the center of the rift valley. However, the next segment north, which is offset almost 50 km along a transform fault, has axial volcanic features that vary in position within the rift valley. In the northern ~half of this segment, lineated small volcanic structures hug the eastern scarp of the rift whereas in the south they are apparent only along the western part of the valley floor. A classic ridge-transform intersection (RTI) nodal deep occurs at this southern end of the segment. The position of the basin is asymmetric relative to the axis, toward the ‘inside corner’ on the eastern side of the rift valley. It is intriguing that the nodal deep, which is often modeled as the result of viscous mantle upwelling and plate stresses at an RTI, is centered on the opposite side of the rift valley from where the most recent volcanic activity occurred. Presumably this reflects interplay between local magma plumbing and tectonic stresses. In addition to the local ridge-transform forces, regional factors associated with subduction along the edge of the Cocos plate may affect mantle flow, melting, and detailed plate kinematics. We will present maps that combine the new Simrad EM122 swath sonar data, obtained during cruise MV1003 aboard R/V Melville, with pre-existing German and Chilean bathymetric grids. We will also discuss some of the tectonic and magmatic implications of the observed detailed morphologic patterns. As one of the few areas on the globe where active subduction and spreading occur in close proximity, the southernmost Chile rise presents a natural laboratory for studying the manifestations of interaction between these processes.

  18. Mantle structure beneath the Afar triple junction derived from surface wave tomography

    NASA Astrophysics Data System (ADS)

    Gallacher, R. J.; Keir, D.; Harmon, N.; Stuart, G. W.; Leroy, S. D.; Hammond, J. O.; Kendall, J. M.; Wondem, A. A.; Gezahegn, B. G.; Ogubazghi, G.

    2013-12-01

    Continental breakup in Afar is generally magma-rich and occurs near the triple junction of the Gulf of Aden (GOA), Red Sea rift and the Main Ethiopian rift (MER). Hypotheses for the source of magmatism associated with this rifting include elevated mantle temperatures resulting from northward migration of hot African Superplume material, and also due to phases of increased decompression melting from rapid plate thinning. To evaluate these hypotheses we conducted a surface wave tomographic experiment using 571 events and 290 stations from 15 seismic networks deployed over the past 12 years. From these data we produced a 3D shear velocity model which constrains the upper 350 km of the Earth, including the lithosphere and uppermost asthenosphere where melt is produced. At 30-100 second periods, our images show a significant (~0.1 km/s) decrease in velocity from the rift flanks into the Afar depression, showing the signature of breakup between Africa and Arabia is still present throughout the mantle. Within Afar, seismic velocities are low, with particularly localised slow anomalies at the 40-second period, beneath the Asal rift (3.57 km/s), Ayelu segment of MER (3.63 km/s) and Dabbahu rift (3.63 km/s) and fast velocities on the rift flanks (3.70-3.80 km/s). These slow anomalies show localised decompression melting and intrusion beneath the rift axis of Afar. Low velocities are also present throughout the mantle beneath the northern section of the MER and in the GOA. Our results show that the mantle beneath Afar still preserves structure from rifting 30 Ma. In addition our results show that localised plate thinning beneath zones of strain focus magmatism to a narrow rift axis.

  19. High Current ESD Test of Advanced Triple Junction Solar Array Coupon

    NASA Technical Reports Server (NTRS)

    Wright, K. H.; Schneider, T. A.; Vaughn, J. A.; Hoang, B.; Wong, F.

    2014-01-01

    A test was conducted on an Advanced Triple Junction (ATJ) coupon that was part of a risk reduction effort in the development of a high-powered solar array design by SSL. The ATJ coupon was a small, 4-cell, two-string configuration that has served as the basic test coupon design used in previous SSL environmental aging campaigns. The coupon has many attributes of the flight design; e.g., substrate structure with graphite face sheets, integrated by-pass diodes, cell interconnects, RTV grout, wire routing, etc. The objective of the present test was to evaluate the performance of the coupon after being subjected to induced electrostatic discharge testing at two string voltages (100 V, 150 V) and four array current (1.65 A, 2.0 A, 2.475 A, and 3.3 A). An ESD test circuit, unique to SSL solar array design, was built that simulates the effect of missing cells and strings in a full solar panel with special primary arc flashover circuitry. A total of 73 primary arcs were obtained that included 7 temporary sustained arcs (TSA) events. The durations of the TSAs ranged from 50 µs to 2.9 ms. All TSAs occurred at a string voltage of 150 V. Post-test Large Area Pulsed Solar Simulator (LAPSS), Dark I-V, and By-Pass Diode tests showed that no degradation occurred due to the TSA events. In addition, the post-test insulation resistance measured was > 50 G-ohms between cells and substrate. These test results indicate a robust design for application to a high-current, high-power mission application.

  20. High Current ESD Test of Advanced Triple Junction Solar Array Coupon

    NASA Technical Reports Server (NTRS)

    Wright, Kenneth H., Jr.; Schneider, Todd A.; Vaughn, Jason A.; Hoang, Bao; Wong, Frankie

    2015-01-01

    A test was conducted on an Advanced Triple Junction (ATJ) coupon that was part of a risk reduction effort in the development of a high-powered solar array design by SSL. The ATJ coupon was a small, 4-cell, two-string configuration that has served as the basic test coupon design used in previous SSL environmental aging campaigns. The coupon has many attributes of the flight design; e.g., substrate structure with graphite face sheets, integrated by-pass diodes, cell interconnects, RTV grout, wire routing, etc. The objective of the present test was to evaluate the performance of the coupon after being subjected to induced electrostatic discharge testing at two string voltages (100 V, 150 V) and four array current (1.65 A, 2.0 A, 2.475 A, and 3.3 A). An ESD test circuit, unique to SSL solar array design, was built that simulates the effect of missing cells and strings in a full solar panel with special primary arc flashover circuitry. A total of 73 primary arcs were obtained that included 7 temporary sustained arcs (TSA) events. The durations of the TSAs ranged from 50 micros to 2.9 ms. All TSAs occurred at a string voltage of 150 V. Post-test Large Area Pulsed Solar Simulator (LAPSS), Dark I-V, and By-Pass Diode tests showed that no degradation occurred due to the TSA events. In addition, the post-test insulation resistance measured was > 50 G-ohms between cells and substrate. These test results indicate a robust design for application to a high-current, high-power mission application.

  1. High Current ESD Test of Advanced Triple Junction Solar Array Coupon

    NASA Technical Reports Server (NTRS)

    Wright, Kenneth H., Jr.; Schneider, Todd A.; Vaughn, Jason A.; Hoang, Bao; Wong, Frankie

    2014-01-01

    Testing was conducted on an Advanced Triple Junction (ATJ) coupon that was part of a risk reduction effort in the development of a high-powered solar array design by Space Systems/Loral, LLC (SSL). The ATJ coupon was a small, 4-cell, two-string configuration that has served as the basic test coupon design used in previous SSL environmental aging campaigns. The coupon has many attributes of the flight design; e.g., substrate structure with graphite face sheets, integrated by-pass diodes, cell interconnects, RTV grout, wire routing, etc. The objective of the present test was to evaluate the performance of the coupon after being subjected to induced electrostatic discharge (ESD) testing at two string voltages (100 V, 150 V) and four array currents (1.65 A, 2.0 A, 2.475 A, and 3.3 A). An ESD test circuit, unique to SSL solar array design, was built that simulates the effect of missing cells and strings in a full solar panel with special primary arc flashover circuitry. A total of 73 primary arcs were obtained that included 7 temporary sustained arcs (TSA) events. The durations of the TSAs ranged from 50 micro-seconds to 2.75 milli-seconds. All TSAs occurred at a string voltage of 150 V. Post-test Large Area Pulsed Solar Simulator (LAPSS), Dark I-V, and By-Pass Diode tests showed that no degradation occurred due to the TSA events. In addition, the post-test insulation resistance measured was > 50 G-ohms between cells and substrate. These test results indicate a robust design for application to a high-current, high-power mission.

  2. Seismicity at the Kairei Hydrothermal Vent Field Near the Rodriguez Triple Junction in the Indian Ocean

    NASA Astrophysics Data System (ADS)

    Sato, T.; Takata, H.; Imai, Y.; Mori, T.; Noguchi, Y.; Kono, A.; Yamada, T.; Shinohara, M.

    2014-12-01

    1. Introduction In the first segment of the central Indian Ridge from the Rodriguez triple junction, the Kairei hydrothermal vent field exists and extrudes hydrothermal fluid with richer hydrogen content compared to other hydrothermal vents in the world. Around the Kairei hydrothermal field, serpentinized peridotite and troctolites, and gabbroic rocks were discovered. These deep-seated rocks exposed around the Kairei field may cause the enrichment of H2 in the Kairei fluids. At the Kairei field, a hydrogen-based subsurface microbial ecosystem and various hydrothermal vent macrofauna were found. In the "TAIGA" Project (Trans-crustal Advection and In situ reaction of Global sub-seafloor Aquifer), this area is a representative field of "TAIGA" of hydrogen. To investigate how the deep-seated rocks (originally situated at several kilometers below seafloor) are uplifted and exposed onto seafloor, and the hydrothermal fluids circulate in subsurface, we conducted a seismic refraction/reflection survey and seismicity observation with ocean bottom seismometers (OBSs). This presentation will show seismicity of the survey area. 2. Observation and results We conducted a seismic survey around the Kairei hydrothermal field from January 27 to March 19 in 2013 using S/V Yokosuka of Jamstec. We used 21 OBSs. From the 50 days seismicity observation, we found many micro earthquakes in this area. A swarm of micro earthquakes exists at a location about 1 km northwest of the Kairei field. The swarm has a NNW-SSE strike, parallel to the ridge axis. The depth of the swarm is very shallow (~4 km from seafloor). This swarm may be related to the hydrothermal activities of the Kairei field. At the first segment of the central Indian Ridge, many micro earthquakes occurred. The depth of these events is deeper than that of the swarm near the Kairei field.

  3. Amorphous silicon research. Phase III technical progress report, August 1, 1996--July 31, 1997

    SciTech Connect

    Guha, S.

    1997-11-01

    The principal objective of this R&D program is to expand, enhance and accelerate knowledge and capabilities for the development of high-performance, two-terminal multijunction hydrogenated amorphous silicon (a-Si) alloy cells and modules. The near-term goal of the program is to achieve 12% stable active-area efficiency using the multijunction approach. The long-term goal is to achieve 15% stable efficiency multijunction modules. The major effort of this program is to develop high efficiency component cells and incorporate them in the triple-junction structure to obtain the highest stable efficiency. New and improved deposition regimes were investigated to obtain better cell performance. Fundamental studies to obtain better understanding of material and cell performance were undertaken.

  4. Numerical modelling of Triple Junction Tectonics at Karlıova, Eastern Turkey: implications for the mechanism of magma transport

    NASA Astrophysics Data System (ADS)

    Karaoǧlu, Özgür; Browning, John; Bazargan, Mohsen; Gudmundsson, Agust

    2016-04-01

    Few places on Earth are as tectonically active as the Karlıova region of eastern Turkey. In this region, complex interactions between the Arabian, Eurasian and Anatolian plates occur at the Karlıova Triple Junction (KTJ). Suitably stressed crustal materials of the extruded block on the Karlıova-type triple junctions are potential regions for magma ascent. The relationship between tectonics and magma propagation in triple junction tectonic settings is, however, poorly understood. This study discusses the mechanism of magma propagation in the Karlıova Triple Junction (KTJ) tectonic regime. We aim to demonstrate how the geometry and mechanical properties of faults and rock units affect magma propagation under a variety of tectonic boundary loads. We discuss the geologic setting of the KTJ and the manifestations of shallow and deeper magma chambers within the crustal segment. Our numerical modelling study aims to quantify the crustal response of various tectonic regimes in Eastern Turkey. The region is characterised by lithological heterogeneity which is considered in our models. We present a series of two-dimensional and three-dimensional numerical models to help constrain evolving ideas regarding inversion and transtensional tectonics in an east-west direction along the KTJ. We also consider a north to south striking profile which is subjected to regional compression and local extensional tectonic phases which likely operated in the region ~3 My. A three-dimensional model is presented to investigate the effect of regional differential stresses. Our numerical models demonstrate that the regional tectonic stresses that are capable of encouraging magma-chamber failure and dyke propagation. Turnadaǧ volcanism at the western part of this triple junction has been fed by a shallow magma chamber located at 8-10 km depth during E-W extension. The Varto caldera is also fed by a shallow magma chamber at 8-10 km depth. Numerical results show that if the region were to be

  5. Atom-scale compositional distribution in InAlAsSb-based triple junction solar cells by atom probe tomography.

    PubMed

    Hernández-Saz, J; Herrera, M; Delgado, F J; Duguay, S; Philippe, T; Gonzalez, M; Abell, J; Walters, R J; Molina, S I

    2016-07-29

    The analysis by atom probe tomography (APT) of InAlAsSb layers with applications in triple junction solar cells (TJSCs) has shown the existence of In- and Sb-rich regions in the material. The composition variation found is not evident from the direct observation of the 3D atomic distribution and because of this a statistical analysis has been required. From previous analysis of these samples, it is shown that the small compositional fluctuations determined have a strong effect on the optical properties of the material and ultimately on the performance of TJSCs. PMID:27306098

  6. Atom-scale compositional distribution in InAlAsSb-based triple junction solar cells by atom probe tomography

    NASA Astrophysics Data System (ADS)

    Hernández-Saz, J.; Herrera, M.; Delgado, F. J.; Duguay, S.; Philippe, T.; Gonzalez, M.; Abell, J.; Walters, R. J.; Molina, S. I.

    2016-07-01

    The analysis by atom probe tomography (APT) of InAlAsSb layers with applications in triple junction solar cells (TJSCs) has shown the existence of In- and Sb-rich regions in the material. The composition variation found is not evident from the direct observation of the 3D atomic distribution and because of this a statistical analysis has been required. From previous analysis of these samples, it is shown that the small compositional fluctuations determined have a strong effect on the optical properties of the material and ultimately on the performance of TJSCs.

  7. Results from an International Measurement Round Robin of III-V Triple Junction Solar Cells under Air Mass Zero

    NASA Technical Reports Server (NTRS)

    Jenkins, Phillip; Scheiman, Chris; Goodbody, Chris; Baur, Carsten; Sharps, Paul; Imaizumi, Mitsuru; Yoo, Henry; Sahlstrom, Ted; Walters, Robert; Lorentzen, Justin; Nocerino, John; Khan, Osman; Cravens, Robert; Valles, Juan; Toporow, Chantal; Gomez, Trinidad,; Bazan, Loreto Pazos; Bailey, Sheila

    2006-01-01

    This paper reports the results of an international measurement round robin of monolithic, triple-junction, GaInP/GaAs/Ge space solar cells. Eight laboratories representing national labs, solar cell vendors and space solar cell consumers, measured cells using in-house reference cells and compared those results to measurements made where each lab used the same set of reference cells. The results show that most of the discrepancy between laboratories is likely due to the quality of the standard cells rather than the measurement system or solar simulator used.

  8. Pinning fault zone strength using small earthquakes in the Mendocino triple junction region recorded by a dense OBS array

    NASA Astrophysics Data System (ADS)

    Chen, X.; McGuire, J. J.

    2014-12-01

    The Mendocino triple junction contains a diversity of fault types including plate boundary strike-slip and thrust faults as well as intraplate faults within the subducting oceanic mantle that are expected to operate under significantly different rheological conditions. We analyze the data from the Cascadia Initiative's Year-2 focused OBS array deployed at the triple junction region. We detect over 1000 earthquakes with magnitude ranging from 1 to 4.5 from Sep 2012 to Feb 2013. Locations refined with waveform cross-correlation arrival time measurements delineate two sub-parallel faults trending NW-SE revealing the complex geometry of the triple junction, as well as a intraplate fault possibly related to the 2010 M6.5 earthquake in the subducted Gorda plate. We are performing a joint inversion for 3D structure and hypocenter locations to further refine the image of the triple junction fault systems. Our primary focus is on examining earthquake rupture mechanics in this complex fault network. Strength envelope calculations predict that the faults within the subducting Gorda plate support differential stress levels that are 1-2 orders of magnitude larger than what is typically assumed for the thrust interface. To determine if this contrast is reflected in the data, we estimate apparent stress for the M>2 earthquakes on the three types of faults. We compute displacement spectra using 2.56s time window from the picked arrival. Spectra with signal-to-noise ratio > 3 between 4 to 10 Hz are saved for further analysis. For the saved spectra, we apply two approaches using EGF method: (1) single event-pair deconvolution, where we select best-similar event pairs using relative locations derived from waveform cross-correlation, (2) iterative stacking deconvolution, where we solve for a event term, a station term and a path term using all the event-station pairs. Once the target event source spectrum is obtained, we compute the stress drop and apparent stress using the

  9. Upper plate contraction north of the migrating Mendocino triple junction northern California: Implications for partitioning of strain

    USGS Publications Warehouse

    McCrory, P.A.

    2000-01-01

    Geologic measurement of permanent contraction across the Cascadia subduction margin constrains one component of the tectonic deformation along the convergent plate boundary, the component critical for the seismic hazard assessment of crustal faults. A comprehensive survey of active faults in onshore subduction margin rocks at the southern end of the Cascadia subduction zone indicates that these thrust faults accommodate ??10 mm/yr of convergence oriented 020??-045??. Seismotectonic models of subduction zones typically assign this upper plate strain to the estimate of aseismic slip on the megathrust. Geodetic models include this permanent crustal strain within estimates of elastic strain accumulation on the megathrust. Both types of models underestimate the seismic hazard associated with crustal faults. Subtracting the observed contraction from the plate convergence rate (40-50 mm/yr; directed 040??-055??) leaves 30-40 mm/yr of convergence to be partitioned between slip on the megathrust, contraction within the southern Juan de Fuca plate, and crustal contraction outside the subduction complex rocks. This simple estimate of slip partitioning neglects the discrepancy between the plate convergence and contraction directions in the vicinity of the Mendocino triple junction. The San Andreas and Cascadia limbs of the Mendocino triple junction are not collinear. The eastern edge of the broad San Andreas boundary is ??85 km east of the Cascadia subduction boundary, and across this zone the Pacific plate converges directly with the North America plate. The skewed orientation of crustal structures just north of the leading edge of the Pacific plate suggests that they are deforming in a hybrid stress field resulting from both Juan de Fuca-North America motion and Pacific-North America motion. The composite convergence direction (50 mm/yr: directed 023??) is consistent with the compressive stress axis (020??) inferred from focal mechanisms of crustal earthquakes in the

  10. Upper plate contraction north of the migrating Mendocino triple junction, northern California: Implications for partitioning of strain

    NASA Astrophysics Data System (ADS)

    McCrory, Patricia A.

    2000-12-01

    Geologic measurement of permanent contraction across the Cascadia subduction margin constrains one component of the tectonic deformation along the convergent plate boundary, the component critical for the seismic hazard assessment of crustal faults. A comprehensive survey of active faults in onshore subduction margin rocks at the southern end of the Cascadia subduction zone indicates that these thrust faults accommodate ˜10 mm/yr of convergence oriented 020°-045°. Seismotectonic models of subduction zones typically assign this upper plate strain to the estimate of aseismic slip on the megathrust. Geodetic models include this permanent crustal strain within estimates of elastic strain accumulation on the megathrust. Both types of models underestimate the seismic hazard associated with crustal faults. Subtracting the observed contraction from the plate convergence rate (40-50 mm/yr; directed 040°-055°) leaves 30-40 mm/yr of convergence to be partitioned between slip on the megathrust, contraction within the southern Juan de Fuca plate, and crustal contraction outside the subduction complex rocks. This simple estimate of slip partitioning neglects the discrepancy between the plate convergence and contraction directions in the vicinity of the Mendocino triple junction. The San Andreas and Cascadia limbs of the Mendocino triple junction are not collinear. The eastern edge of the broad San Andreas boundary is ˜85 km east of the Cascadia subduction boundary, and across this zone the Pacific plate converges directly with the North America plate. The skewed orientation of crustal structures just north of the leading edge of the Pacific plate suggests that they are deforming in a hybrid stress field resulting from both Juan de Fuca-North America motion and Pacific-North America motion. The composite convergence direction (50 mm/yr; directed 023°) is consistent with the compressive stress axis (020°) inferred from focal mechanisms of crustal earthquakes in the

  11. New geodetic measurements in central Afar constraining the Arabia-Somalia-Nubia triple junction kinematics

    NASA Astrophysics Data System (ADS)

    Doubre, C.; Deprez, A.; Masson, F.; Socquet, A.; Lewi, E.; Grandin, R.; Calais, E.; Wright, T. J.; Bendick, R. O.; Pagli, C.; Peltzer, G.; de Chabalier, J. B.; Ibrahim Ahmed, S.

    2014-12-01

    Abhe, suggesting that this area represents the most probable location for the triple junction.

  12. Three-dimensional crustal structure of the Mendocino Triple Junction region from local earthquake travel times

    NASA Astrophysics Data System (ADS)

    Verdonck, David; Zandt, George

    1994-12-01

    The large-scale, three-dimensional geometry of the Mendocino Triple Junction at Cape Mendocino, California, was investigated by inverting nearly 19,000 P wave arrival times from over 1400 local earthquakes to estimate the three-dimensional velocity structure and hypocentral parameters. A velocity grid 175 km (N-S) by 125 km (E-W) centered near Garberville, California, was constructed with 25 km horizontal and 5 km vertical mode spacing. The model was well resolved near Cape Mendocino, where the earthquakes and stations are concentrated. At about 40.6 N latitude a high-velocity gradient between 6.5 and 7.5 km/s dips gently to the south and east from about 15 km depth near the coast. Relocated hypocenters concentrate below this high gradient which we interpret as the oceanic crust of the subducted Gorda Plate. Therefore the depth to the top of the Gorda Plate near Cape Mendocino is interpreted to be approximately 15 km. The Gorda Plate appears intact and dipping approximately 8 deg eastward due to subduction and flexing downward 6 deg - 12 deg to the south. Both hypocenters and velocity structure suggest that the southern edge of the plate intersects the coastline at 40.3 N latitude and maintains a linear trend 15 deg south of east to at least 123 W longitude. The top of a large low-velocity region at 20-30 km depth extends about 50 km N-S and 75 km E-W (roughly between Garberville and Covelo) and is located above and south of the southern edge of the Gorda Plate. We interpret this low velocity area to be locally thickened crust (8-10 km) due to either local compressional forces associated with north-south compression caused by the northward impingement of the rigid Pacific Plate or by underthrusting of the base of the accretionary subduction complex at the southern terminous of the Cascadia Subduction Zone. South of Cape Mendocino and southwest of the Garberville fault, high velocities indicative of oceanic crust are detected at 15 km depth. We interpret this

  13. Fluid overpressures on the San Andreas Fault following the passage of the Mendocino Triple Junction

    NASA Astrophysics Data System (ADS)

    Fulton, P. M.; Saffer, D. M.; Bekins, B. A.

    2004-12-01

    Fluid pressures significantly greater than hydrostatic have been hypothesized to account for the weak nature of many large plate-boundary faults. However, on the San Andreas Fault, the hypothesized subsurface processes which could create, sustain, and potentially localize such pressures over millions of years are not well understood. In this study, we use two-dimensional finite element models of coupled fluid flow and heat transport perpendicular to the fault to evaluate hypothesized mechanisms for generating elevated pore pressure. The models account for transient changes in crustal geotherm and thickness of the seismogenic crust in response to the passage of the Mendocino Triple Junction. Theoretical curves of whole-rock fluid content as functions of pressure and temperature allow us to calculate fluid sources due to metamorphic dehydration within the Franciscan mélange as a function of depth and thermal history. Average fluid sources in the seismogenic crust range from 10-18 to 10-16 s-1 over the 15 Myr spanned by our models. We consider a variety of permeability distributions within the models, including a range of homogenous permeability and depth-dependent permeability. We also consider heterogeneous permeability distributions reflecting fault properties and geologic features such as serpentine sills. Our results show that over 15 Myr, thermal expansion of pore fluids due to initial burial, followed by additional heating during exhumation, can create significant overpressures. In addition, models which include fluid sources from metamorphic dehydration of the Franciscan mélange result in pore pressures approaching a significant fraction of lithostatic. Generally, all model results show overpressures extending several kilometers to each side of the fault. Due to the continual nature of many of these processes, overpressures are sustained for millions of years without the need for complex and/or extremely low-permeability seals. Models which include geologic

  14. Magnetic Gradiometer and Vector Magnetometer Survey of the Galapagos Triple Junction

    NASA Astrophysics Data System (ADS)

    Gee, J.; Cande, S. C.; Parker, R. L.; Lonsdale, P. F.; Bowles, J.

    2004-05-01

    Several fundamental tectonic problems of the equatorial Pacific remain unsolved due to the lack of magnetic anomaly data. A basic limitation encountered with the use of the standard proton precession magnetometer (or any total field instrument) is that total field anomalies over approximately N/S striking bodies are very small at low magnetic latitudes. Another problem encountered with magnetic surveys near the magnetic equator are the diurnal variations associated with the external field. Measurements of the vector anomalous field and total field gradient offer ways to overcome these limitations. Total field gradiometer data allow recognition and removal of time dependent external field variations. Vector magnetic anomalies provide two distinct advantages over total field measurements. Although the total field anomalies are small (typically 50 nT) over most of the equatorial Pacific, the vertical and horizontal components of the anomalous field are 2-5 times larger. In addition, vector anomaly data can be used to evaluate the two dimensionality of the magnetic source since the along track and vertical anomalies are related by a 90o phase shift for a perfectly two dimensional source. To evaluate the advantages of these systems, we conducted a survey of the trails of the Galapagos triple junction using both a high resolution total field gradiometer and a vector magnetometer. The longitudinal gradiometer system consists of two Overhauser sensors (0.01 nT sensitivity) towed 350 and 450m behind the survey vessel. The towed vector magnetometer utilizes a commercial motion reference sensor (0.02o orientation accuracy with three fluxgate sensors) suitable for measuring horizontal and vertical anomalies as small as 30-50 nT. Vector anomalies across Cocos-Nazca crust corroborate the high degree of linearity of these E/W lineations; horizontal and vertical anomalies exhibit high coherence (>0.9) and the expected 90o phase relationship at wavelengths longer than ~8km. Vector

  15. Three-dimensional crustal structure for the Mendocino Triple Junction region from local earthquake travel times

    SciTech Connect

    Verdonck, D.; Zandt, G.

    1994-12-10

    The large-scale, three-dimensional geometry of the Mendocino Triple Junction at Cape Mendocino, California, was investigated by inverting nearly 19,000 P wave arrival times from over 1400 local earthquakes to estimate the three-dimensional velocity structure and hypocentral parameters. A velocity grid 175 km (N-S) by 125 km (E-W) centered near Garberville, California, was constructed with 25 km horizontal and 5 km vertical node spacing. The model was well resolved near Cape Mendocino, where the earthquakes and stations are concentrated. At about 40.6{degrees}N latitude a high-velocity gradient between 6.5 and 7.5 km/s dips gently to the south and east from about 15 km depth near the coast. Relocated hypocenters concentrate below this high gradient which the authors interpret as the oceanic crust of the subducted Gorda Plate. Therefore the depth to the top of the Gorda Plate near Cape Mendocino is interpreted to be {approximately} 15 km. The Gorda Plate appears intact and dipping {approximately}8{degrees} eastward due to subduction and flexing downward 6{degrees}-12{degrees} to the south. Both hypocenters and velocity structure suggest that the southern edge of the plate intersects the coastline at 40.3{degrees}N latitude and maintains a linear trend 15{degrees} south of east to at least 123{degrees}W longitude. The top of a large low-velocity region at 20-30 km depth extends about 50 km N-S and 75 km E-W (roughly between Garberville and Covelo) and is located above and south of the southern edge of the Gorda Plate. The authors interpret this low velocity area to be locally thickened crust (8-10 km) due to either local compressional forces associated with north-south compression caused by the northward impingement of the rigid Pacific Plate or by underthrusting of the base of the accretionary subduction complex at the southern terminous of the Cascadia Subduction Zone. 66 refs., 11 figs., 3 tabs.

  16. Amorphous silicon research Phase I. Annual subcontract report, August 1, 1994--July 31, 1995

    SciTech Connect

    Guha, S.

    1995-10-01

    The Principal objective of this R&D program is to expand, enhance and accelerate knowledge and capabilities for the development of high-performance, two-terminal multifunction hydrogenated amorphous silicon (a-Si:H) alloy modules. The near-term goal of the program is to achieve 12% stable efficiency by 1998 using the multifunction approach. The major effort of this program is to develop high efficiency component cells and incorporate them in the triple-junction structure to obtain the highest stable efficiency. The bulk of the effort was directed toward the middle and bottom cell structure. New and improved deposition regimes were investigated to obtain better cell performance. Fundamental studies to obtain better understanding of material and cell performance were undertaken.

  17. Simulation of Temperature Characteristics of InGaP/InGaAs/Ge Triple-Junction Solar Cell under Concentrated Light

    NASA Astrophysics Data System (ADS)

    Sakurada, Yuya; Ota, Yasuyuki; Nishioka, Kensuke

    2011-04-01

    Using an equivalent circuit model, the temperature characteristics of an InGaP/InGaAs/Ge triple-junction solar cell under concentrated light conditions were analyzed in detail. The current-voltage (I-V) characteristics of the single-junction solar cells (InGaP, InGaAs, and Ge solar cells) were measured at various temperatures. From the dark I-V characteristics of each single-junction solar cell, the diode parameters and temperature exponents were extracted. The extracted diode parameters and temperature exponents were applied to the equivalent circuit model for the triple-junction solar cell, and the solar-cell performance was calculated. There was good agreement between the measured and calculated I-V characteristics of the triple-junction solar cell at various temperatures under concentrated light conditions.

  18. Lower plate deformation at the Chile Triple Junction from the paleomagnetic record (45°30'S-46°S)

    NASA Astrophysics Data System (ADS)

    Lagabrielle, Yves; Bourgois, Jacques; Dyment, Jerôme; Pelletier, Bernard

    2015-08-01

    During the Chile Triple Junction (CTJ) cruise, geophysical surveys were conducted between 45°S and 48°S, in the region of the Chile Triple Junction (CTJ), where the Nazca and Antarctica Plates are subducting beneath the South American Plate. Near the CTJ, the South Chile Rise (SCR), which separates the Nazca and Antarctica lower plates, consists of three spreading segments trending ~N160°, separated by a series of parallel fracture zones. The active spreading centers of the three segments consist of grabens with various widths and depths, bounded by steep fault scarps. We provide robust data showing that the SCR recorded remote and long-term effects of ridge subduction far from the subduction front. Magnetic profiles, multibeam bathymetric, and seismic data were acquired at intervals of 13 km along a N80°E direction across the SCR during the CTJ cruise of R/V L'Atalante. Deformation of the oceanic lithosphere includes (1) a segmentation of the spreading axes along strike, (2) some ridge jumps, and (3) local constriction and changes in trend of the fracture zone valleys. Off-axis volcanism is observed in places that may suggest a link with an abnormal stress field induced by ridge subduction. The tectonic and volcanic anomalies, which occurred in response to the subduction of the SCR1 axis, may be correlated with geochemical anomalies and slab fragmentation recognized by previous works.

  19. Late Cenozoic transpressional ductile deformation north of the Nazca?South America?Antarctica triple junction

    NASA Astrophysics Data System (ADS)

    Cembrano, José; Lavenu, Alain; Reynolds, Peter; Arancibia, Gloria; López, Gloria; Sanhueza, Alejandro

    2002-09-01

    The southern Andes plate boundary zone records a protracted history of bulk transpressional deformation during the Cenozoic, which has been causally related to either oblique subduction or ridge collision. However, few structural and chronological studies of regional deformation are available to support one hypothesis or the other. We address along- and across-strike variations in the nature and timing of plate boundary deformation to better understand the Cenozoic tectonics of the southern Andes. Two east-west structural transects were mapped at Puyuhuapi and Aysén, immediately north of the Nazca-South America-Antarctica triple junction. At Puyuhuapi (44°S), north-south striking, high-angle contractional and strike-slip ductile shear zones developed from plutons coexist with moderately dipping dextral-oblique shear zones in the wallrocks. In Aysén (45-46°), top to the southwest, oblique thrusting predominates to the west of the Cenozoic magmatic arc, whereas dextral strike-slip shear zones develop within it. New 40Ar- 39Ar data from mylonites and undeformed rocks from the two transects suggest that dextral strike-slip, oblique-slip and contractional deformation occurred at nearly the same time but within different structural domains along and across the orogen. Similar ages were obtained on both high strain pelitic schists with dextral strike-slip kinematics (4.4±0.3 Ma, laser on muscovite-biotite aggregates, Aysén transect, 45°S) and on mylonitic plutonic rocks with contractional deformation (3.8±0.2 to 4.2±0.2 Ma, fine-grained, recrystallized biotite, Puyuhuapi transect). Oblique-slip, dextral reverse kinematics of uncertain age is documented at the Canal Costa shear zone (45°S) and at the Queulat shear zone at 44°S. Published dates for the undeformed protholiths suggest both shear zones are likely Late Miocene or Pliocene, coeval with contractional and strike-slip shear zones farther north. Coeval strike-slip, oblique-slip and contractional

  20. Advances in amorphous silicon alloy-based multijunction cells and modules

    SciTech Connect

    Guha, S.; Yang, J.; Banerjee, A.; Glatfelter, T.; Xu, X. )

    1992-12-01

    Multijunction amorphous silicon alloy-based solar cells and modules offer the potential of obtaining high efficiency with long-term stability against light-induced degradation. We have studied the stability of the component cells of the multijunction devices prepared under different deposition conditions. We observe a definite correlation between the microstructure of the intrinsic material and initial and light-degraded performance of the cells. Using suitable deposition conditions and optimum matching of the component cells, we have fabricated double-junction dual-bandgap cells which show stabilized active-area efficiency of 11% after 600 hours of one-sun illumination at 50 [degree]C. Double-junction and triple-junction modules of 900 cm[sup 2] area have been fabricated, and the performance of these panels will be discussed.

  1. Research on stable, high-efficiency amorphous silicon multijunction modules

    SciTech Connect

    Guha, S. )

    1991-12-01

    This report describes research to improve the understanding of amorphous silicon alloys and other relevant non-semiconductor materials for use in high-efficiency, large-area multijunction modules. The research produced an average subcell initial efficiency of 8.8% over a 1-ft{sup 2} area using same-band-gap, dual-junction cells deposited over a ZnO/AlSi back reflector. An initial efficiency of 9.6% was achieved using a ZnO/Ag back reflector over smaller substrates. A sputtering machine will be built to deposit a ZnO/Ag back reflector over a 1-ft{sup 2} area so that a higher efficiency can also be obtained on larger substrates. Calculations have been performed to optimize the grid pattern, bus bars, and cell interconnects on modules. With our present state of technology, we expect a difference of about 6% between the aperture-area and active-area efficiencies of modules. Preliminary experiments show a difference of about 8%. We can now predict the performance of single-junction cells after long-term light exposure at 50{degree}C by exposing cells to short-term intense light at different temperatures. We find that single-junction cells deposited on a ZnO/Ag back reflector show the highest stabilized efficiency when the thickness of the intrinsic layers is about 2000 {angstrom}. 8 refs.

  2. Performance and reliability of a 30-kW triple-junction photovoltaic receiver for 500X concentrator dish or central receiver applications

    NASA Astrophysics Data System (ADS)

    Verlinden, P. J.; Lewandowski, A.; Lasich, J. B.

    2006-08-01

    Over the last 15 years, Solar Systems has developed a dense array receiver PV technology for 500X concentrator reflective dish applications. This concentrator PV technology has been successfully deployed at six different locations in Australia, counting for about 1 MWp of installed peak power. A new Multijunction III-V receiver to replace the current silicon Point-Contact solar cells has recently been developed. The new receiver technology is based on high-efficiency (> 32%) Concentrator Ultra Triple Junction (CUTJ) solar cells from Spectrolab, resulting in system power and energy performance improvement of more than 50% compared to the silicon cells. The 0.235 m2 concentrator PV receiver, designed for continuous 500X operation, is composed of 64 dense array modules, and made of series and parallel-connected solar cells, totaling approximately 1,500 cells. The individual dense array modules have been tested under high intensity pulsed light, as well as with concentrated sunlight at the Solar Systems research facility and at the National Renewable Energy Laboratory's High Flux Solar Furnace. The efficiency of the dense array modules ranges from 30% to 36% at 500X (50 W/cm2, AM1.5D low AOD, 21°C). The temperature coefficients for power, voltage and current, as well as the influence of Air Mass on the cell responsivity, were measured. The reliability of the dense array multijunction III-V modules has been studied with accelerated aging tests, such as thermal cycling, damp heat and high-temperature soak, and with real-life high-intensity exposure. The first 33-kWp multijunction III-V receiver was recently installed in a Solar Systems dish and tested in real-life 500X concentrated sunlight conditions. Receiver efficiencies of 30.3% and 29.0% were measured at Standard Operating Conditions and Normal Operating Conditions respectively.

  3. The Angular Performance Behavior Of Triple Junction Solar Cells With Different Antireflection Coatings For High Temperature Space Missions

    NASA Astrophysics Data System (ADS)

    Hulsheger, Tim; Brandt, Christian; Caon, Antonio; Fiebrich, Horst K.; Andreev, Thomas

    2011-10-01

    The angular behavior of GaInP2/GaAs/Ge triple junction solar cells is studied from 0° up to 86°. Angle dependent short circuit currents of cells with antireflection coatings such as TiO2/Al2O3 and Al2O3 are compared to results of uncoated cells. Performance benefits from each coating are measured before and after cover glass coverage. Related temperature effects are predicted taking into account measured absorption coefficients in order to address on the coating of choice for high temperature solar generators. The influence of the sun light intensities from 1 AM0 to 8 AM0 is put in relation with basic semiconductor properties.

  4. Research on stable, high-efficiency amorphous silicon multijunction modules

    SciTech Connect

    Bhat, P.K.; Brown, S.; Hollingsworth, R.; Shen, D.S.; del Cueto, J.; Iwanicko, E.; Marshall, C.; DeHart, C.; Mentor, D.; Benson, A.; Matovich, C.; Sandwisch, J. )

    1991-04-01

    This report describes a contract to produce multijunction modules based entirely on amorphous silicon alloys, the modules having an aperture area of at least 900 cm{sup 2} and a stable, reproducible conversion efficiency of at least 6.5% after 600 hours of light exposure (air mass 1.5) at 50{degrees} C. The work focussed on (1) producing opto-electronic-grade amorphous silicon material for band gaps of about 1.7 and 1.9 eV by changing the hydrogen content in the film bonded to the silicon, (2) studying and obtaining data on the light stability of single-junction p-i-n solar cells with gaps of about 1.7 and 1.9 eV, and (3) analyzing losses in a silicon/silicon multijunction cell. We report new results on an indium tin oxide (ITO)/silver back contact and the deposition of granular tin oxide by atmospheric-pressure chemical vapor deposition. Progress toward module fabrication at the end of six months has been good, with the demonstration of 5.4% initial efficiency in a silicon/silicon multijunction submodule with an aperture area of 4620 cm{sup 2} and incorporating devices with 2nd-junction i-layer thicknesses of about 3500 {angstrom}. We also demonstrated a single-junction silicon submodule with an aperture area of 4620 cm{sup 2}, a thickness of about 3500 {angstrom}, and an initial efficiency of 6.5%. 4 refs., 39 figs., 5 tabs.

  5. Use of very-high-frequency plasmas to prepare a-Si:H-based triple-junction solar cells at high deposition rates: Annual technical status report, 11 March 1998--11 March 1999

    SciTech Connect

    Jones, S.J.; Liu, T.; Tsu, D.; Izu, M.

    1999-10-25

    This report describes work performed by Energy Conversion Devices, Inc. (ECD) during this phase of this subcontract. ECD researchers have made significant progress in advancing the very high frequency (VHF), high-rate technology. They demonstrated that 8.0% stable efficiencies can be achieved for a-Si:H cells whose i-layers are prepared at rates near 10 {angstrom}/s using the VHF technique. Presently, there is not a great difference in the performance of a-Si:H cells made using the VHF technique and i-layer deposition rates near 10 {angstrom}/s and that for cells made using the standard 13.56 MHz technique and rates near 1 {angstrom}/s in the same deposition system. In terms of the a-SiGe:H cells, researchers have completed a number of studies of devices with properties appropriate for middle-junction cells-that is, cells without Ag/ZnO back-reflectors having Voc values near 0.75V and Jsc values near 8.0 mA/cm{sup 2} when measured using AM1.5 light filtered using a 530-nm, low-band-pass filter. The stabilized proper ties for these cells prepared at i-layer rates near 10 {angstrom}/s are again similar to a-SiGe:H cells made using the same deposition hardware and the low-rate 13.56 MHz method. Establishing an initial 10.5% for a triple-junction cell whose i-layers are prepared at the high rates sets the baseline for ECD's future studies. The triple-junction cell degradation (10%--13%) with prolonged light soaking is similar to that regularly obtained for cells prepared at low i-layer deposition rates (1 {angstrom}/s). This is important because the use of high-rate methods to prepare i-layers typically leads to less-stable materials and cells. Increasing the buffer-layer deposition rate to 6 {angstrom}/s leads to nearly a 15-min decrease in the total deposition time, whereas the increase in the n-layer and p-layer deposition rates both decrease the total time by 5 and 5.8 min, respectively. Thus, besides the i-layer growth rates, increasing the buffer layer growth

  6. Fore-arc Counterclockwise Rotation In Southern Mexico: Implications For The NA-CA-CO Triple Junction

    NASA Astrophysics Data System (ADS)

    Andreani, L.; Le Pichon, X.; Rangin, C.; Martinez-Reyes, J.

    2007-12-01

    Numerous studies, mainly based on structural and paleomagnetic data, consider the Southern Mexico as a crustal block (Southern Mexico Block, SMB) uncoupled from the North American plate with a southeast motion with respect to North America accommodated by extension through the central Trans-Mexican Volcanic Belt (TMVB). On the other hand, the accommodation of this motion on the southeastward boundary, especially at the Cocos/Caribbean/North American triple junction is still debated. The boundary between the SMB and the North American plate is constituted by three connected zones of deformation: (1) left-lateral transtension across the central TMVB, (2) left-lateral strike-slip faulting along the eastern TMVB and Veracruz area and (3) reverse and left- lateral strike-slip faulting in the Chiapas area. We show that these three active deformation zones accommodate a couterclockwise rotation of the SMB with respect to the North American plate. We specially discuss the Quaternary motion of the SMB with respect to the surrounding plates near the Cocos/Caribbean/North American triple junction. The model we propose predicts a Quaternary couterclockwise rotation of 0.45 deg/Ma with a pole located at 24.2N and 91.8W. Finally we discuss the geodynamic implications of this counterclockwise rotation. The Southern Mexico Block motion is generally assumed to be the result of slip partitioning at the trench. However the obliquity of the subduction is too small to explain slip partitioning. The motion could be facilitated by the high thermal gradient and gravitational collapse that affects central Mexico or by partial coupling with the eastward motion of the Caribbean plate.

  7. Assessment of Late Quaternary strain partitioning in the Afar Triple Junction: Dobe and Hanle grabens, Ethiopia and Djibouti

    NASA Astrophysics Data System (ADS)

    Polun, S. G.; Stockman, M. B.; Hickcox, K.; Horrell, D.; Tesfaye, S.; Gomez, F. G.

    2015-12-01

    As the only subaerial exposure of a ridge - ridge - ridge triple junction, the Afar region of Ethiopia and Djibouti offers a rare opportunity to assess strain partitioning within this type of triple junction. Here, the plate boundaries do not link discretely, but rather the East African rift meets the Red Sea and Gulf of Aden rifts in a zone of diffuse normal faulting characterized by a lack of magmatic activity, referred to as the central Afar. An initial assessment of Late Quaternary strain partitioning is based on faulted landforms in the Dobe - Hanle graben system in Ethiopia and Djibouti. These two extensional basins are connected by an imbricated accommodation zone. Several fault scarps occur within terraces formed during the last highstand of Lake Dobe, around 5 ka - they provide a means of calibrating a numerical model of fault scarp degradation. Additional timing constraints will be provided by pending exposure ages. The spreading rates of both grabens are equivalent, however in Dobe graben, extension is partitioned 2:1 between northern, south dipping faults and the southern, north dipping fault. Extension in Hanle graben is primarily focused on the north dipping Hanle fault. On the north margin of Dobe graben, the boundary fault bifurcates, where the basin-bordering fault displays a significantly higher modeled uplift rate than the more distal fault, suggesting a basinward propagation of faulting. On the southern Dobe fault, surveyed fault scarps have ages ranging from 30 - 5 ka with uplift rates of 0.71, 0.47, and 0.68 mm/yr, suggesting no secular variation in slip rates from the late Plestocene through the Holocene. These rates are converted into horizontal stretching estimates, which are compared with regional strain estimated from velocities of relatively sparse GPS data.

  8. Dynamics of plume-triple junction interaction: Results from a series of three-dimensional numerical models and implications for the formation of oceanic plateaus

    NASA Astrophysics Data System (ADS)

    Dordevic, Mladen; Georgen, Jennifer

    2016-03-01

    Mantle plumes rising in the vicinity of mid-ocean ridges often generate anomalies in melt production and seafloor depth. This study investigates the dynamical interactions between a mantle plume and a ridge-ridge-ridge triple junction, using a parameter space approach and a suite of steady state, three-dimensional finite element numerical models. The top domain boundary is composed of three diverging plates, with each assigned half-spreading rates with respect to a fixed triple junction point. The bottom boundary is kept at a constant temperature of 1350°C except where a two-dimensional, Gaussian-shaped thermal anomaly simulating a plume is imposed. Models vary plume diameter, plume location, the viscosity contrast between plume and ambient mantle material, and the use of dehydration rheology in calculating viscosity. Importantly, the model results quantify how plume-related anomalies in mantle temperature pattern, seafloor depth, and crustal thickness depend on the specific set of parameters. To provide an example, one way of assessing the effect of conduit position is to calculate normalized area, defined to be the spatial dispersion of a given plume at specific depth (here selected to be 50 km) divided by the area occupied by the same plume when it is located under the triple junction. For one particular case modeled where the plume is centered in an intraplate position 100 km from the triple junction, normalized area is just 55%. Overall, these models provide a framework for better understanding plateau formation at triple junctions in the natural setting and a tool for constraining subsurface geodynamical processes and plume properties.

  9. High efficiency neutron sensitive amorphous silicon pixel detectors

    SciTech Connect

    Mireshghi, A.; Cho, G.; Drewery, J.S.; Hong, W.S.; Jing, T.; Lee, H.; Kaplan, S.N.; Perez-Mendez, V.

    1993-11-01

    A multi-layer a-Si:H based thermal neutron detector was designed, fabricated and simulated by Monte Carlo method. The detector consists of two PECVD deposited a-Si:H pin detectors interfaced with coated layers of Gd, as a thermal neutron converter. Simulation results indicate that a detector consisting of 2 Gd films with thicknesses of 2 and 4 {mu}m, sandwiched properly with two layers of sufficiently thick ({approximately}30{mu}m) amorphous silicon diodes, has the optimum parameters. The detectors have an intrinsic efficiency of about 42% at a threshold setting of 7000 electrons, with an expected average signal size of {approximately}12000 electrons which is well above the noise. This efficiency will be further increased to nearly 63%, if we use Gd with 50% enrichment in {sup 157}Gd. We can fabricate position sensitive detectors with spatial resolution of 300 {mu}m with gamma sensitivity of {approximately}1 {times} 10{sup {minus}5}. These detectors are highly radiation resistant and are good candidates for use in various application, where high efficiency, high resolution, gamma insensitive position sensitive neutron detectors are needed.

  10. Thin-film amorphous silicon alloy research partnership. Phase 2, Annual technical progress report, 2 February 1996--1 February 1997

    SciTech Connect

    Guha, S

    1997-06-01

    This is Phase II of a 3-phase, 3-year program. It is intended to expand, enhance, and accelerate knowledge and capabilities for developing high-performance, two-terminal multijunction amorphous Si alloy modules. We discuss investigations on back reflectors to improve cell performance and investigate uniformity in performance over a 1-sq.-ft. area. We present results on component cell performance, both in the initial and in the light-degraded states, deposited over a 1-sq.-ft. area. The uniformity in deposited is investigated by studying the performance of subcells deposited over the entire area. We also present results on the performance of triple- junction cells and modules. The modules use grid-lines and encapsulants compatible with our production technology. We discuss the novel laser-processing technique that has bee developed at United Solar to improve energy-conversion efficiency and reduce manufacturing costs. We discuss in detail the optimization of the processing steps, and the performance of a laser-processed, triple- junction device of 12.6 cm{sup 2} area is presented. We also present experimental results on investigations of module reliability.

  11. Seismic structure at the Kairei Hydrothermal vent field near the Rodriguez Triple Junction in the Indian Ocean

    NASA Astrophysics Data System (ADS)

    Takata, H.; Sato, T.; Imai, Y.; Mori, T.; Noguchi, Y.; Kono, A.; Yamada, T.; Shinohara, M.

    2014-12-01

    Central Indian Ridge is located at the north of the Rodriguez Triple Junction and shows slow-intermediate spreading rate. The Kairei hydrothermal Field (KHF) was discovered in the first segment of Central Indian Ridge near the Rodriguez Triple Junction. The vent fluid which is extruding at the KHF has higher H2 content compared with other hydrothermal vent fluid in the world. Although The KHF itself exists above a basaltic rock massif, gabbro and mafic rocks were discovered on the seafloor around the KHF. These deep-seated rocks may contribute to the high H2concentration of the Kairei vent fluid .To understand how gabbro and mafic rocks are uplifted and exhumed on the seafloor, we conducted a seismic refraction/reflection survey using ocean bottom seismograms (OBSs). We conducted the seismic refraction/reflection survey from January 27 to March 19 in 2013 using S/V Yokosuka of Jamstec. In the experiment, we used 21 OBSs, an air gun (G.I.gun) and a single channel steamer cable. We obtained 5 survey lines NNW-SSE direction parallel to the ridge axis, 5 lines E-W direction and 5 lines NNE-SSW direction. In addition to these lines, we acquired other 5 lines passing through the point above the KHF or Yokoniwa Rise, which is the north of the KHF. In analysis of refraction data, firstly, we estimated 2D velocity model under survey lines, which are parallel to the ridge axis, using the progressive model development method developed by Sato and Kennett (2000). Then, we constructed a 3D initial model and run the 3D tomographic method developed by Zelt and Barton (1998). The 1D velocity profile of the KHF seems to be similar to that of mid ocean ridges such as Mid Atlantic Ridge, East Pacific Rise. Seismic velocities under the KHF and Yokoniwa Rise reach about 6km/s at depth of 1~2 km below seafloor, probably indicating uplift of deep-seated rocks. In this presentation we will show 3D seismic structure of this area.

  12. The angular velocity of Nubia relative to Somalia and the location of the Nubia-Somalia-Antarctica triple junction

    NASA Astrophysics Data System (ADS)

    Horner-Johnson, Benjamin C.; Gordon, Richard G.; Cowles, Sara M.; Argus, Donald F.

    2005-07-01

    A new analysis of geologically current plate motion across the Southwest Indian ridge (SWIR) and of the current location of the Nubia-Antarctica-Somalia triple junction is presented. Spreading rates averaged over the past 3.2 Myr are estimated from 103 well-distributed, nearly ridge-perpendicular profiles that cross the SWIR. All available bathymetric data are evaluated to estimate the azimuths and uncertainties of transform faults; six are estimated from multibeam data and 12 from precision depth recorder (PDR) data. If both the Nubian and Somalian component plates are internally rigid near the SWIR and if the Nubia-Somalia boundary is narrow where it intersects the SWIR, that intersection lies between ~26°E and ~32°E. Thus, the boundary is either along the spreading ridge segment just west of the Andrew Bain transform fault complex (ABTFC) or along some of the transform fault complex itself. These limits are narrower than and contained within limits of ~24°E to ~33°E previously found by Lemaux et al. from an analysis of the locations of magnetic anomaly 5. The data are consistent with a narrow boundary, but also consistent with a diffuse boundary as wide as ~700 km. The new Nubia-Somalia pole of rotation lies ~10° north of the Bouvet triple junction, which places it far to the southwest of southern Africa. The new angular velocity determined only from data along the SWIR indicates displacement rates of Somalia relative to Nubia of 3.6 +/- 0.5 mm yr-1 (95 per cent confidence limits) towards 176° (S04° E) between Somalia and Nubia near the SWIR, and of 8.3 +/- 1.9 mm yr-1 (95 per cent confidence limits) towards 121° (S59° E) near Afar. The new Nubia-Somalia angular velocity differs significantly from the Nubia-Somalia angular velocity estimated from Gulf of Aden and Red sea data. This significant difference has three main alternative explanations: (i) that the plate motion data have substantial unmodelled systematic errors, (ii) that the Nubian component

  13. Wide-angle seismic constraints on the evolution of the deep San Andreas plate boundary by Mendocino triple junction migration

    USGS Publications Warehouse

    Hole, J.A.; Beaudoin, B.C.; Henstock, T.J.

    1998-01-01

    Recent wide-angle seismic observations that constrain the existence and structure of a mafic layer in the lower crust place strong constraints on the evolution of the San Andreas plate boundary system in northern and central California. Northward migration of the Mendocino Triple Junction and the subducted Juan de Fuca lithospheric slab creates a gap under the continent in the new strike-slip system. This gap must be filled by either asthenospheric upwelling or a northward migrating slab attached to the Pacific plate. Both processes emplace a mafic layer, either magmatic underplating or oceanic crust, beneath the California Coast Ranges. A slab of oceanic lithosphere attached to the Pacific plate is inconsistent with the seismic observation that the strike-slip faults cut through the mafic layer to the mantle, detaching the layer from the Pacific plate. The layer could only be attached to the Pacific plate if large vertical offsets and other complex structures observed beneath several strike-slip faults are original oceanic structures that are not caused by the faults. Otherwise, if oceanic slabs exist beneath California, they do not migrate north to fill the growing slab gap. The extreme heat pulse created by asthenospheric upwelling is inconsistent with several constraints from the seismic data, including a shallower depth to the slab gap than is predicted by heat flow models, seismic velocity and structure that are inconsistent with melting or metamorphism of the overlying silicic crust, and a high seismic velocity in the upper mantle. Yet either the Pacific slab model or the asthenospheric upwelling model must be correct. While the mafic material in the lower crust could have been emplaced prior to triple junction migration, the deeper slab gap must still be filled. A preexisting mafic layer does not reduce the inconsistencies of the Pacific slab model. Such material could, however, compensate for the decrease in mafic magma that would be produced if

  14. Lithosphere/Asthenosphere Structure beneath the Mendocino Triple Junction from the Analysis of Surface Wave, Ambient Noise, and Receiver Functions

    NASA Astrophysics Data System (ADS)

    Liu, K.; Zhai, Y.; Levander, A.; Porritt, R. W.; Allen, R. M.; Schmandt, B.; Humphreys, E.; O'Driscoll, L.

    2010-12-01

    We have developed a 3-D shear velocity model using finite-frequency Rayleigh wave phase velocity dispersion, PdS receiver functions, and ambient noise tomography to better understand the complex lithosphere/asthenosphere structures in the Mendocino Triple Junction (MTJ) region. Using approximately 100 events (July 2007-December 2008) recorded by the stations of the Flexible Array Mendocino Experiment (FAME), the USArray Transportable Array (TA) network, and the Berkeley Digital Seismograph network, we have obtained the phase velocities (20-100s) from the finite-frequency Rayleigh wave tomography, which agrees well with the ambient noise tomography results (7-40 s, Porritt & Allen, 2010) in the overlapping period range. We subsequently inverted for a 3-D Vs model on a 0.25°x0.25° grid from the combined dispersion datasets, constrained by interface depths from the PdS receiver functions (Zhai & Levander, 2010). The resulting crustal and upper mantle Vs model (~150 km) reveals strong lateral heterogeneity in the subduction and transform regimes of the Mendocino Triple Junction region where the Gorda, Pacific, and North American plates intersect. The subducting Gorda slab is well-imaged as an eastward-dipping high-velocity anomaly to ~100 km depth. At the same depth to the east we observe a large-scale low velocity zone, which is the mantle wedge beneath the North American Plate. The southern edge of the Gorda plate (SEDGE) is imaged at 80-100 km depth and is in excellent agreement with measurements made from PdS receiver functions, body-wave tomography (Schmandt & Humphreys, 2010; Obrebski et al., 2010), and active source studies. At depths greater than 80 km, we interpret low velocities under the Cascadia subduction zone as the asthenosphere below the Gorda plate, in agreement with measured LAB depths from RFs. South of the SEDGE shallow strong low-velocities appear beneath the transform region, which we interpret as the asthenosphere in the slab-gap region left by

  15. Research on stable, high-efficiency amorphous silicon multijunction modules

    SciTech Connect

    Ghosh, M.; DelCueto, J.: Kampas, F.; Xi, J. )

    1993-02-01

    This report describes results from the first phase of a three-phase contract for the development of stable, high-efficiency, same-band-gap, amorphous silicon (a-Si) multijunction photovoltaic (PV) modules. The program involved improving the properties of individual layers of semiconductor and non-semiconductor materials and small-area single-junction and multijunction devices, as well as the multijunction modules. The semiconductor materials research was performed on a-Si p, i, and n layers, and on microcrystalline silicon n layers. These were deposited using plasma-enhanced chemical vapor deposition. The non-semiconductor materials studied were tin oxide, for use as a transparent-conducting-oxide (TCO), and zinc oxide, for use as a back reflector and as a buffer layer between the TCO and the semiconductor layers. Tin oxide was deposited using atmospheric-pressure chemical vapor deposition. Zinc oxide was deposited using magnetron sputtering. The research indicated that the major challenge in the fabrication of a-Si multijunction PV modules is the contact between the two p-i-n cells. A structure that has low optical absorption but that also facilitates the recombination of electrons from the first p-i-n structure with holes from the second p-i-n structure is required. Non-semiconductor layers and a-Si semiconductor layers were tested without achieving the desired result.

  16. Lithospheric evolution in response to triple junction migration: A program to obtain seismic images of the MTJ region

    SciTech Connect

    Trehu, A. ); Beaudoin, B.; Klemperer, S. ); Levander, A. ); Meltzer, A. ); Carver, G. ); Furlong, K. ); Talwani, M. ); Clarke, S.; Mooney, W.; Wells, R. ); Zandt, G. )

    1993-04-01

    The authors will be conducting an integrated seismic experiment to image the structure of the crust and upper mantle of northern California immediately before and after passage of the Mendocino Triple Junction. The purpose of this representation is to describe the project to other scientists interested in geological and geophysical processes in this region and to solicit input relevant to detailed siting of the funded seismic profiles. The experiment encompasses two field seasons: onshore seismic refraction/wide angle reflection data acquisition along three long profiles scheduled for late summer, 1993; and MCS deep crustal seismic reflection data acquisition accompanied by simultaneous large aperture recording using both ocean bottom and onshore seismographs, tentatively scheduled for summer, 1994. This study represents a component of a long-term, multi-disciplinary effort on the part of many investigators to exploit this well defined system as an in-situ laboratory to study geodynamic processes associated with the transition from a convergent to a transform plate boundary and to evaluate the implications for continental growth and evolution.

  17. Terrace Formation in the Upper Headwater Region of the Mattole River Watershed Across the Mendocino Triple Junction, Northwest California

    NASA Astrophysics Data System (ADS)

    Robinson, M.; Flanagan, S., II; Hemphill-Haley, M. A.

    2015-12-01

    The Mattole River, in northwestern California, is located in a tectonically active and geologically complex area, the Mendocino triple junction (MTJ), where the North American, Pacific and Gorda plates meet. The Mattole River does not follow the classic river "concave-up" profile. Instead, the river headwaters have wide valleys of low gradient fill, cut and strath terraces with deeply incised active channels. In fact, the river has a "convex-up" profile with a low gradient headwater leading to a higher gradient midcourse. Terrace formation in the upper headwater region of the Mattole River records times of disequilibrium of channel profile and incision as the river responds to changes that are, in large part, due to the passage of the northwardly migrating, thermally buoyant MTJ. In order to investigate the distribution and relative ages of terraces, detailed surveys of terrace surfaces and bedrock strath positions were conducted along four headwater tributaries: Thompson Creek, Baker Creek, Lost River and Ancestor Creek. Additionally, across the terraces, hand borings were excavated to bedrock to provide a three dimensional image of terrace thickness. Terrace morphology and stratigraphy provide information on terrace forming mechanisms and timing. This study includes high-resolution geomorphic data regarding the relation of Mattole headwater terraces to the MTJ, as well as provides more temporal information about the fluvial system's response to the ongoing northward migration of the MTJ.

  18. Tectonics of the Afar triple junction from InSAR and GPS derived strain maps and seismicity

    NASA Astrophysics Data System (ADS)

    Pagli, Carolina; Ebinger, Cynthia; Yun, Sang-Ho; Keir, Derek; Wang, Hua

    2016-04-01

    Strain and seismicity show us the mode by which deformation is accommodated in rifting continents. Here we present a combined analysis of InSAR and GPS derived strain maps and seismicity to understand the tectonics of the current Afar triple junction plate boundary zone. Our results show that that the plate spreading motion is accommodated in different ways in the Red Sea Rift after jumping southeastward along the Gulf of Aden Rift. At the Red Sea Rift, extension and shear are coupled with seismicity, occurring both along-rift but also in areas off-rift. In the Gulf of Aden Rift extension and normal faulting occur in the central parts of the rifts while at the rifts tips strike-slip earthquakes are observed. The extensional strains occur over a broad zone encompassing several overlapping rifts. Conversely the strike-slip earthquakes are focused along a narrow EW trending lineament. The pattern suggests that the recent history of magmatic intrusions in the Red Sea Rift still dominates the plate boundary deformation inducing earthquakes even in areas off-rift and with no previous faults mapped. On the other hand, in the Gulf of Aden Rift our strain and seismicity maps are consistent mainly with extensional tectonics occurring over an exceptionally broad zone (over 200 km). We interpret the strike-slip earthquakes observed at the rift tips as the result of shearing at the rifts tips where the extension terminates against continental lithosphere.

  19. Source Parameter Studies of Historical and Recent Earthquakes of the Cascadia Subduction Zone and Mendocino Triple Junction Region

    NASA Astrophysics Data System (ADS)

    Wiest, K. R.; Theiner, T. R.; Velasco, A. A.; Doser, D. I.

    2003-12-01

    We are comparing the seismograms of recent (post-1989) earthquakes to those of historic earthquakes (pre-1966) recorded at the same (or similar) station locations to determine how comparable the historic earthquakes are to recent events with well determined hypocenters and rupture parameters. The seismograms of recent events will be used as empirical Greens functions in a deconvolution process to more accurately determine the directivity and rupture process of the older events. Our initial work in the Cascadia Subduction zone has focused on earthquakes within the subducting Pacific plate occurring in 1939, 1946, 1949 and 1965, in locations similar to the 1999 Satsop and 2001 Nisqually earthquakes. Preliminary analysis of waveform information suggests that the 1949 Olympia earthquake has a different rupture history to the east and south of the epicenter, as compared to the Nisqually earthquake. In the Mendocino Triple Junction region, we have focused on modeling smaller magnitude earthquakes using an earth simplification transform. We will calibrate the technique using several intermediate magnitude events that have occurred on the Mendocino fault and within the Gorda plate.

  20. Landslides, threshold slopes, and the survival of relict terrain in the wake of the Mendocino Triple Junction

    NASA Astrophysics Data System (ADS)

    Bennett, Georgina; Miller, Scott; Roering, Joshua; Schmidt, David

    2016-04-01

    Establishing the coupled fluvial-hillslope response to uplift is critical for interpreting sediment fluxes, stream channel characteristics, hazard potential and topographic development. Threshold-slope models purport that landslide fluxes obtain a balance with river incision in response to rapid rock uplift, but a lack of observations and constraints in most settings prevents us from quantifying the process-linkages required for channels and hillslopes to adjust to tectonic forcing. We mapped landslides and knickpoints and extracted topographic metrics across the northern Californian Coast ranges, where the landscape is responding to a wave of rapid uplift related to the migration of the Mendocino Triple Junction (MTJ). We find a tightly coupled channel-landslide-hillslope response to uplift from catchment to regional scales. Locally, landslide erosion rates estimated from historical air photo analyses approach 1 mm yr-1, consistent with published cosmogenic nuclide and suspended sediment erosion rates as well as modeled isostatic uplift associated with crustal thickening proximal to the MTJ. Landslides are concentrated along channel reaches downstream of migrating knickpoints generated by base level fall at channel outlets and hillslope gradients and relief become invariant with the onset of significant landslide erosion. Following passage of the MTJ, this coupled response becomes inhibited by subsidence due to crustal thinning and landslide-derived coarse sediment delivery that suppresses catchment-wide channel incision and knickpoint migration. As a result, substantial portions of the landscape escape comprehensive adjustment to increased uplift and retain the signature of a gentle and slow-eroding relict landscape.

  1. Upper plate responses to active spreading ridge/transform subduction: The tectonics, basin evolution, and seismicity of the Taita area, Chile Triple Junction

    SciTech Connect

    Flint, S.; Prior, D. ); Styles, P.; Murdie, R. ); Agar, S.; Turner, P. )

    1993-02-01

    Integrated field geophysical, structural and stratigraphic studies are attempting to elucidate the mechanisms and consequences of the Late Miocene-present day subduction of the Chile Ridge triple junction system. Preliminary data indicate a shallow plane of seismicity at about 15 km to 20 km depth below the Taitao peninsula. The depths correspond to the predicted depth range of subducted upper ocean crust. The calculated Bouguer anomaly map cannot be explained by the upper plate geology, suggesting that gravity is influenced by heterogeneities in the subducting oceanic plate. Seismic data imply that a subducted transform system underlying the inner Taitao Peninsula is still an active structure. A series of Middle-Late Tertiary sedimentary basins lie inboard of the triple junction. Within the Cosmelli basin, abrupt marine to continental facies transitions give clear evidence of base level changes. The amount of basinward shift of facies across sequence boundaries gets progressively greater up stratigraphy, indicating progressively greater base level changes. The lower part of the basin fill is folded and then thrusted eastward as a series of imbricates, while the overlying, greater thickness of fluvial sediments are only gently tilted westwards. We provisionally interpret this geometry to indicate that the early basin fill was deforming due to contractional tectonics while the later basin fill was being deposited. This complex basin history may reflect initiation and development of triple junction subduction.

  2. Investigation of InGaP/(In)AlGaAs/GaAs triple-junction top cells for smart stacked multijunction solar cells grown using molecular beam epitaxy

    NASA Astrophysics Data System (ADS)

    Sugaya, Takeyoshi; Mochizuki, Toru; Makita, Kikuo; Oshima, Ryuji; Matsubara, Koji; Okano, Yoshinobu; Niki, Shigeru

    2015-08-01

    We report high-quality InGaP/(In)AlGaAs/GaAs triple-junction solar cells fabricated using solid-source molecular beam epitaxy (MBE) for the first time. The triple-junction cells can be used as top cells for smart stacked multijunction solar cells. A growth temperature of 480 °C was found to be suitable for an (In)AlGaAs second cell to obtain high-quality tunnel junctions. The properties of AlGaAs solar cells were better than those of InAlGaAs solar cells when a second cell was grown at 480 °C. The high-quality InGaP/AlGaAs/GaAs solar cell had an impressive open-circuit voltage of 3.1 V. This result indicates that high-performance InGaP/AlGaAs/GaAs triple-junction solar cells can be fabricated using solid-source MBE.

  3. Tectonics and geology of spreading ridge subduction at the Chile Triple Junction: a synthesis of results from Leg 141 of the Ocean Drilling Program

    USGS Publications Warehouse

    Behrmann, J.H.; Lewis, S.D.; Cande, S.C.

    1994-01-01

    An active oceanic spreading ridge is being subducted beneath the South American continent at the Chile Triple Junction. This process has played a major part in the evolution of most of the continental margins that border the Pacific Ocean basin. A combination of high resolution swath bathymetric maps, seismic reflection profiles and drillhole and core data from five sites drilled during Ocean Drilling Program (ODP) Leg 141 provide important data that define the tectonic, structural and stratigraphic effects of this modern example of spreading ridge subduction. A change from subduction accretion to subduction erosion occurs along-strike of the South American forearc. This change is prominently expressed by normal faulting, forearc subsidence, oversteepening of topographic slopes and intensive sedimentary mass wasting, overprinted on older signatures of sediment accretion, overthrusting and uplift processes in the forearc. Data from drill sites north of the triple junction (Sites 859-861) show that after an important phase of forearc building in the early to late Pliocene, subduction accretion had ceased in the late Pliocene. Since that time sediment on the downgoing oceanic Nazca plate has been subducted. Site 863 was drilled into the forearc in the immediate vicinity of the triple junction above the subducted spreading ridge axis. Here, thick and intensely folded and faulted trench slope sediments of Pleistocene age are currently involved in the frontal deformation of the forearc. Early faults with thrust and reverse kinematics are overprinted by later normal faults. The Chile Triple Junction is also the site of apparent ophiolite emplacement into the South American forearc. Drilling at Site 862 on the Taitao Ridge revealed an offshore volcanic sequence of Plio-Pleistocene age associated with the Taitao Fracture Zone, adjacent to exposures of the Pliocene-aged Taitao ophiolite onshore. Despite the large-scale loss of material from the forearc at the triple junction

  4. Amorphous solar cells: Characteristics and efficiency. (Latest citations from the Aerospace database). Published Search

    SciTech Connect

    Not Available

    1993-11-01

    The bibliography contains citations concerning development, efficiency, and design of amorphous solar cells. Film properties, deterioration, hydrogenation, cell stability, and performance characteristics are discussed. (Contains 250 citations and includes a subject term index and title list.)

  5. Accomodation of the deformation in the Cocos-Caribbean-North America triple junction area, from GPS meaurements

    NASA Astrophysics Data System (ADS)

    Franco, A.; Lasserre, C.; Lyon-Caen, H.; Molina, E.; Kostoglodov, V.; Barrier, E.; Figueroa, C.

    2008-12-01

    Northern Central America is located in a complex zone of interaction between three major tectonic plates: the North American (NA), the Caribbean (CA) and the Cocos (CO) plates. While the CO plate is subducting under the NA and CA plates along the Mid-American trench, the on-land relative motion between the NA and CA plates is mainly accommodated by the east-west trending left-lateral Polochic-Motagua fault system. We use GPS data to characterize the deformation in this CO-CA-NA triple junction area in terms of interactions and relative contributions of the different structures (Polochic and Motagua faults, a series of north-south grabens south of them and the Mid-American Volcanic Arc, MAVA), and coupling at the subduction interface. We analyse GPS-campaign data from different networks in Guatemala (24 sites measured in 1999-2003- 2006), Salvador (3 sites measured in 2003 and 2006) and Chiapas, southern Mexico (8 sites measured each year from 2002 to 2004). Data are processed and combined using the GAMIT/GLOBK softwares. The obtained velocity field is first fitted using simple elastic models. The Motagua fault seems to accomodate most of the present left-lateral motion between CA and NA, with less than 30 procent taken by the Polochic fault despite its comparable surface morphology, historical seismicity and microseismic activity (that we recorded during a 6 months experiment in 2005). This may suggest complex mechanical interactions between the Motagua and Polochic faults at the scale of several seismic cycles. A single fault model, centered on the Motagua fault, locked at a depth of 15 km, indicates a slip rate decrease from eastern (20 mm/yr) to central Guatemala (10 mm/yr) towards the CA-CO-NA triple junction (0 mm/yr?). This decrease seems to be consistent with east-west extension rates estimated across the Ipala and Guatemala city grabens south of the Motagua fault. We also observe a right-lateral movement across the MAVA: 15mm/yr in western Salvador and 10mm

  6. The role of the Little salmon fault in accommodating deformation associated with the migration of the Mendocino triple junction

    NASA Astrophysics Data System (ADS)

    Leroy, T. H.; Oswald, J.; Williams, T.; McPherson, R.

    2012-12-01

    The boundary between the southern terminus of the Cascadia subduction zone (Csz) and the northern termination of the San Andreas transform system presents a unique opportunity to investigate crustal deformation at a migrating triple junction. This boundary is the trench-transform-transform Mendocino triple junction (MTJ), the northwesterly migrating intersection of the Pacific, Gorda/Juan De Fuca, and the North American plates. We use recent and published geologic, geomorphic, geodetic, seismic, and other available geophysical data to characterize the on-shore areas north and south of the MTJ and propose a deformation model for the boundary where e-w subduction gives way to NW translation. North of the MTJ and at the southern end of the Csz, the fold and thrust belt associated with the subducting plate interface is manifest on-land as several zones of northeasterly convergent thrust faults. Observations indicate that faults, focal mechanisms and other stress field indicators systematically change strike as you move from north to south within the on-land portion of the fold and thrust belt. Features in the north demonstrate a more north northwesterly strike than the features in the south which tend to strike more northwesterly as they approach the latitude of the MTJ. This is particularly true for the southernmost fault of the fold and thrust belt, the Little salmon fault (Lsf) which changes strike from roughly N30W at its northern exposure to approximately East-west at its southern exposure over a distance of 27 km. Geologic and paleoseismic data suggests the LSF accommodates significantly more horizontal contraction than the other faults of the southern Csz fold and thrust belt. South of the MTJ the northern San Andreas fault system consists of three primary fault splays that accommodate about 80% of the total Pacific-North American plate boundary motion. The primary faults from west to east are the San Andreas, Maacama, and Bartlett Springs fault zones. Fault

  7. Middle Miocene paleotemperature anomalies within the Franciscan Complex of northern California: Thermo-tectonic responses near the Mendocino triple junction

    USGS Publications Warehouse

    Underwood, M.B.; Shelton, K.L.; McLaughlin, R.J.; Laughland, M.M.; Solomon, R.M.

    1999-01-01

    This study documents three localities in the Franciscan accretionary complex of northern California, now adjacent to the San Andreas fault, that were overprinted thermally between 13.9 and 12.2 Ma: Point Delgada-Shelter Cove (King Range terrane); Bolinas Ridge (San Bruno Mountain terrane); and Mount San Bruno (San Bruno Mountain terrane). Vein assemblages of quartz, carbonate, sulfide minerals, and adularia were precipitated locally in highly fractured wall rock. Vitrinite reflectance (Rm) values and illite crystallinity decrease away from the zones of metalliferous veins, where peak wall-rock temperatures, as determined from Rm, were as high as 315??C. The ??18O values of quartz and calcite indicate that two separate types of fluid contributed to vein precipitation. Higher ??18O fluids produced widespread quartz and calcite veins that are typical of the regional paleothermal regime. The widespread veins are by-products of heat conduction and diffuse fluid flow during zeolite and prehnite-pumpellyite-grade metamorphism, and we interpret their paleofluids to have evolved through dehydration reactions and/or extensive isotopic exchange with accreted Franciscan rocks. Lower ??18O fluids, in contrast, evolved from relatively high temperature exchange between seawater (or meteoric water) and basaltic and/or sedimentary host rocks; focused flow of those fluids resulted in local deposition of the metalliferous veins. Heat sources for the three paleothermal anomalies remain uncertain and may have been unrelated to one another. Higher temperature metalliferous fluids in the King Range terrane could have advected either from a site of ridge-trench interaction north of the Mendocino fracture zone or from a "slabless window" in the wake of the northward migrating Mendocino triple junction. A separate paradox involves the amount of Quaternary offset of Franciscan basement rocks near Shelter Cove by on-land faults that some regard as the main active trace of the San Andreas

  8. Arc lavas on both sides of a trench: Slab window effects at the Solomon Islands triple junction, SW Pacific

    NASA Astrophysics Data System (ADS)

    Chadwick, John; Perfit, Michael; McInnes, Brent; Kamenov, George; Plank, Terry; Jonasson, Ian; Chadwick, Claire

    2009-03-01

    The Woodlark Spreading Center (WSC) is subducted at the San Cristobal trench, forming a triple junction at the New Georgia Group (NGG) arc in the Solomon Islands. WSC lavas are N-MORB at > 100 km from the trench, but with decreasing distance they have increasingly arc-like Sr-Nd-Pb isotopic ratios, enrichments in Rb > K > Pb > Sr, and depletions in HFSE and Y. Within 50 km of the trench on the Simbo and Ghizo Ridges, many recovered samples are island arc tholeiites to medium-K calc-alkaline andesites and dacites, and many have the same or similar major and trace element and isotopic characteristics as true arc lavas in the NGG on the other side of the trench. Previous investigations have concluded that these WSC lavas are the result of relic back arc mantle enrichments resulting from subduction of the Pacific plate prior to the late Miocene at the North Solomon trench, > 200 km to the north. However, the high-silica WSC lavas are more arc-like than those recovered from other distal back arcs, and are more voluminous, forming large submarine ridges and stratovolcanoes. We suggest that true arc mantle migrates across the plate boundary from the adjacent NGG arc through slab windows created by the subduction of the WSC. This leads to variable mixing between NGG arc and WSC N-MORB end-members, forming the transitional lavas recovered from the WSC. Lavas with similar arc-like characteristics have previously been recovered on the Chile Rise near where it is subducted at the Chile Trench, raising the possibility that such mantle transfer is a common phenomenon where active spreading centers are subducted. The presence of slab windows may also be responsible for the unusual forearc volcanism in the NGG, and melting of slab window margins may account for the presence of high-silica adakite-like lavas on the WSC.

  9. Seismic structure of the southern Cascadia subduction zone and accretionary prism north of the Mendocino triple junction

    USGS Publications Warehouse

    Gulick, S.P.S.; Meltzer, A.M.; Clarke, S.H., Jr.

    1998-01-01

    Four multichannel-seismic reflection profiles, collected as part of the Mendocino triple junction seismic experiment, image the toe of the southern Cascadia accretionary prism. Today, 250-600 m of sediment is subducting with the Gorda plate, and 1500-3200 m is accreting to the northern California margin. Faults imaged west and east of the deformation front show mixed structural vergence. A north-south trending, 20 km long portion of the central margin is landward vergent for the outer 6-8 km of the toe of the prism. This region of landward vergence exhibits no frontal thrust, is unusually steep and narrow, and is likely caused by a seaward-dipping backstop close to the deformation front. The lack of margin-wide preferred seaward vergence and wedge-taper analysis suggests the prism has low basal shear stress. The three southern lines image wedge-shaped fragments of oceanic crust 1.1-7.3 km in width and 250-700 m thick near the deformation front. These wedges suggest shortening and thickening of the upper oceanic crust. Discontinuities in the seafloor west of the prism provide evidence for mass wasting in the form of slump blocks and debris fans. The southernmost profile extends 75 km west of the prism imaging numerous faults that offset both the Gorda basin oceanic crust and overlying sediments. These high-angle faults, bounding basement highs, are interpreted as strike-slip faults reactivating structures originally formed at the spreading ridge. Northeast or northwest trending strike-slip faults within the basin are consistent with published focal mechanism solutions and are likely caused by north-south Gorda-Pacific plate convergence. Copyright 1998 by the American Geophysical Union.

  10. The Angular Velocity of Nubia Relative to Somalia and the Location of the Nubia-Somalia-Antarctica Triple Junction

    NASA Astrophysics Data System (ADS)

    Horner-Johnson, B. C.; Gordon, R. G.; Cowles, S. M.; Argus, D. F.

    2003-12-01

    A new analysis of geologically current plate motion across the Southwest Indian Ridge and of the current location of the Nubia-Antarctica-Somalia triple junction is presented. We estimate spreading rates averaged over the past 3.2 Myr from 103 well-distributed, nearly ridge-perpendicular profiles crossing the Southwest Indian Ridge. We evaluate all available bathymetric data to estimate the azimuths and uncertainties of transform faults; six are estimated from multi-beam data and twelve from precision depth recorder data. If the Nubia-Somalia boundary is narrow where it intersects the Southwest Indian Ridge, that intersection lies between about 26° E and 32° E. This places it either along the spreading ridge segment just west of the Andrew Bain transform fault complex or along the transform fault complex itself. These limits are narrower than, and contained within, limits of about 24° E to 33° E previously found by Lemaux et al. (2002) from an analysis of the locations of magnetic anomaly 5. The data are consistent with a narrow boundary, but also consistent with a diffuse boundary as wide as about 700 km. The new Nubia-Somalia pole of rotation lies southwest of southern Africa and differs significantly from previously estimated poles, including that from data in the Red Sea and Gulf of Aden. The new pole indicates displacement rates of Somalia relative to Nubia of 3.4 +/- 1.3\\ mm yr-1 (95% confidence limits) towards 176.8° between Somalia and Nubia near the Southwest Indian Ridge, and of 8.4 +/- 1.3\\ mm yr-1 (95% confidence limits) towards 118.5° near Afar.

  11. Middle Miocene swift migration of the TTT triple junction and rapid crustal growth in southwest Japan: A review

    NASA Astrophysics Data System (ADS)

    Kimura, Gaku; Hashimoto, Yoshitaka; Kitamura, Yujin; Yamaguchi, Asuka; Koge, Hiroaki

    2014-07-01

    We review recent progress in geological and geophysical investigation in SW Japan, Nankai Trough, and Philippine Sea Plate (PSP), and propose a hypothesis for the Miocene tectonics in SW Japan driven by middle Miocene swift migration of the TTT (trench-trench-trench) triple junction. The new hypothesis is based on the new interpretations as follows. Near-trench magmatism in the outer zone of SW Japan is ascribed to a collision of proto-Izu arc in addition to the previous model of an oceanic ridge of the Shikoku Basin and hot PSP subduction. The indentation structures at Capes Ashizuri, Muroto in Shikoku, and Shiono on the Kii Peninsula were previously explained by "kink folding" due to recent E-W compression. We alternatively suppose the collision of the active arc or topographic peaks such as seamounts inferred from geological and experimental observations. The main crustal component in SW Japan is suggested to be of igneous plutonic rocks rather than the previous interpretation of Cretaceous to Tertiary accretionary complexes. This is typically illustrated in the outer zone to the north of Capes Ashizuri, Muroto, and Shiono from geophysical observation of gravity anomalies, velocity and resistivity, together with geological estimations of caldera age and the size of its root pluton. Episodic crustal growth due to intrusion of igneous rock and subduction of the PSP may have stopped after approximately 12 Ma and restarted at approximately 6 Ma. Our emphasis for this gap is a cessation and resurgence of subduction rather than the previous interpretation, i.e., decreasing of subduction rate.

  12. Seismic structure of the southern Cascadia subduction zone and accretionary prism north of the Mendocino triple junction

    NASA Astrophysics Data System (ADS)

    Gulick, Sean P. S.; Meltzer, Anne M.; Clarke, Samuel H., Jr.

    1998-11-01

    Four multichannel-seismic reflection profiles, collected as part of the Mendocino triple junction seismic experiment, image the toe of the southern Cascadia accretionary prism. Today, 250-600 m of sediment is subducting with the Gorda plate, and 1500-3200 m is accreting to the northern California margin. Faults imaged west and east of the deformation front show mixed structural vergence. A north-south trending, 20 km long portion of the central margin is landward vergent for the outer 6-8 km of the toe of the prism. This region of landward vergence exhibits no frontal thrust, is unusually steep and narrow, and is likely caused by a seaward-dipping backstop close to the deformation front. The lack of margin-wide preferred seaward vergence and wedge-taper analysis suggests the prism has low basal shear stress. The three southern lines image wedge-shaped fragments of oceanic crust 1.1-7.3 km in width and 250-700 m thick near the deformation front. These wedges suggest shortening and thickening of the upper oceanic crust. Discontinuities in the seafloor west of the prism provide evidence for mass wasting in the form of slump blocks and debris fans. The southernmost profile extends 75 km west of the prism imaging numerous faults that offset both the Gorda basin oceanic crust and overlying sediments. These high-angle faults, bounding basement highs, are interpreted as strike-slip faults reactivating structures originally formed at the spreading ridge. Northeast or northwest trending strike-slip faults within the basin are consistent with published focal mechanism solutions and are likely caused by north-south Gorda-Pacific plate convergence.

  13. Formation of hydrothermal deposits at Kings Triple Junction, northern Lau back-arc basin, SW Pacific: The geochemical perspectives

    NASA Astrophysics Data System (ADS)

    Paropkari, Anil L.; Ray, Durbar; Balaram, V.; Surya Prakash, L.; Mirza, Imran H.; Satyanarayana, M.; Gnaneshwar Rao, T.; Kaisary, Sujata

    2010-04-01

    An inactive hydrothermal field was discovered near Kings Triple Junction (KTJ) in northern Lau back-arc basin during 19th cruise of R/V Akademik Mstislav Keldysh in 1990. The field consisted of a large elongated basal platform 'the pedestal' with several 'small' chimneys on its periphery and one 'main mound' superposed over it. The surrounding region is carpeted with lava pillows having ferromanganese 'precipitate' as infillings. The adjoining second field consisted of small chimney like growths termed as 'Christmas Tree' Field. The basal pedestal, the peripheral chimneys and small 'Christmas Tree' like growths (samples collected by MIR submersibles), though parts of the same hydrothermal field, differ significantly in their mineralogy and elemental composition indicating different history of formation. The pedestal slab consisting of chalcopyrite and pyrite as major minerals and rich in Cu is likely to have formed at higher temperatures than sphalerite dominated peripheral chimney. Extremely low concentration of high field strength elements (e.g. Zr, Hf, Nb and Ta) and enrichment of light REE in these sulfides indicate prominent influence of aqueous arc-magma, rich in subduction components. The oxide growths in the 'Christmas Tree' Field have two distinct layers, Fe rich orange-red basal part which seems to have formed at very low temperature as precipitates from diffused hydrothermal flows from the seafloor whereas Mn rich black surface coating is formed from hydrothermal fluids emanated from the seafloor during another episode of hydrothermal activity. Perhaps this is for the first time such unique hydrothermal oxide growths are being reported in association with hydrothermal system. Here, we discuss the possible processes responsible for the formation of these different hydrothermal deposits based on their mineralogy and geochemistry.

  14. Evolution of the Gorda Escarpment, San Andreas fault and Mendocino triple junction from multichannel seismic data collected across the northern Vizcaino block, offshore northern California

    USGS Publications Warehouse

    Godfrey, N.J.; Meltzer, A.S.; Klemperer, S.L.; Trehu, A.M.; Leitner, B.; Clarke, S.H., Jr.; Ondrus, A.

    1998-01-01

    The Gorda Escarpment is a north facing scarp immediately south of the Mendocino transform fault (the Gorda/Juan de Fuca-Pacific plate boundary) between 126??W and the Mendocino triple junction. It elevates the seafloor at the northern edge of the Vizcaino block, part of the Pacific plate, ??? 1.5 km above the seafloor of the Gorda/Juan de Fuca plate to the north. Stratigraphy interpreted from multichannel seismic data across and close to the Gorda Escarpment suggests that the escarpment is a relatively recent pop-up feature caused by north-south compression across the plate boundary. Close to 126??W. the Vizcaino block acoustic basement shallows and is overlain by sediments that thin north toward the Gorda Escarpment. These sediments are tilted south and truncated at the seafloor. By contrast, in a localized region at the eastern end of the Gorda Escarpment, close to the Mendocino triple junction, the top of acoustic basement dips north and is overlain by a 2-km-thick wedge of pre-11 Ma sedimentary rocks that thickens north, toward the Gorda Escarpment. This wedge of sediments is restricted to the northeast corner of the Vizcaino block. Unless the wedge of sediments was a preexisting feature on the Vizcaino block before it was transferred from the North American to the Pacific plate, the strong spatial correlation between the sedimentary wedge and the triple junction suggests the entire Vizcaino block, with the San Andreas at its eastern boundary, has been part of the Pacific plate since significantly before 11 Ma.

  15. Evolution of the Gorda Escarpment, San Andreas Fault and Mendocino triple junction from multichannel seismic data collected across the northern Vizcaino block, offshore northern California

    NASA Astrophysics Data System (ADS)

    Godfrey, Nicola J.; Meltzer, Anne S.; Klemperer, Simon L.; Tréhu, Anne M.; Leitner, Beate; Clarke, Samuel H., Jr.; Ondrus, Amy

    1998-10-01

    The Gorda Escarpment is a north facing scarp immediately south of the Mendocino transform fault (the Gorda/Juan de Fuca-Pacific plate boundary) between 126°W and the Mendocino triple junction. It elevates the seafloor at the northern edge of the Vizcaino block, part of the Pacific plate, ˜1.5 km above the seafloor of the Gorda/Juan de Fuca plate to the north. Stratigraphy interpreted from multichannel seismic data across and close to the Gorda Escarpment suggests that the escarpment is a relatively recent pop-up feature caused by north-south compression across the plate boundary. Close to 126°W, the Vizcaino block acoustic basement shallows and is overlain by sediments that thin north toward the Gorda Escarpment. These sediments are tilted south and truncated at the seafloor. By contrast, in a localized region at the eastern end of the Gorda Escarpment, close to the Mendocino triple junction, the top of acoustic basement dips north and is overlain by a 2-km-thick wedge of pre-11 Ma sedimentary rocks that thickens north, toward the Gorda Escarpment. This wedge of sediments is restricted to the northeast corner of the Vizcaino block. Unless the wedge of sediments was a preexisting feature on the Vizcaino block before it was transferred from the North American to the Pacific plate, the strong spatial correlation between the sedimentary wedge and the triple junction suggests the entire Vizcaino block, with the San Andreas at its eastern boundary, has been part of the Pacific plate since significantly before 11 Ma.

  16. Mesoscopic nonequilibrium thermodynamics of solid surfaces and interfaces with triple junction singularities under the capillary and electromigration forces in anisotropic three-dimensional space.

    PubMed

    Ogurtani, Tarik Omer

    2006-04-14

    A theory of irreversible thermodynamics of curved surfaces and interfaces with triple junction singularities is elaborated to give a full consideration of the effects of the specific surface Gibbs free energy anisotropy in addition to the diffusional anisotropy, on the morphological evolution of surfaces and interfaces in crystalline solids. To entangle this intricate problem, the internal entropy production associated with arbitrary virtual displacements of triple junction and ordinary points on the interfacial layers, embedded in a multicomponent, multiphase, anisotropic composite continuum system, is formulated by adapting a mesoscopic description of the orientation dependence of the chemical potentials in terms of the rotational degree of freedom of individual microelements. The rate of local internal entropy production resulted generalized forces and conjugated fluxes not only for the grain boundary triple junction transversal and longitudinal movements, but also for the ordinary points. The natural combination of the mesoscopic approach coupled with the rigorous theory of irreversible thermodynamics developed previously by the global entropy production hypothesis yields a well-posed, nonlinear, moving free-boundary value problem in two-dimensional (2D) space, as a unified theory. The results obtained for 2D space are generalized into the three-dimensional continuum by utilizing the invariant properties of the vector operators in connection with the descriptions of curved surfaces in differential geometry. This mathematical model after normalization and scaling procedures may be easily adapted for computer simulation studies without introducing any additional phenomenological system parameters (the generalized mobilities), other than the enlarged concept of the surface stiffness. PMID:16626230

  17. Arabia-Somalia plate kinematics, evolution of the Aden-Owen-Carlsberg triple junction, and opening of the Gulf of Aden

    NASA Astrophysics Data System (ADS)

    Fournier, Marc; Chamot-Rooke, Nicolas; Petit, Carole; Huchon, Philippe; Al-Kathiri, Ali; Audin, Laurence; Beslier, Marie-Odile; D'Acremont, Elia; Fabbri, Olivier; Fleury, Jean-Marc; Khanbari, Khaled; Lepvrier, Claude; Leroy, Sylvie; Maillot, Bertrand; Merkouriev, Serge

    2010-04-01

    New geophysical data collected at the Aden-Owen-Carlsberg (AOC) triple junction between the Arabia, India, and Somalia plates are combined with all available magnetic data across the Gulf of Aden to determine the detailed Arabia-Somalia plate kinematics over the past 20 Myr. We reconstruct the history of opening of the Gulf of Aden, including the penetration of the Sheba Ridge into the African continent and the evolution of the triple junction since its formation. Magnetic data evidence three stages of ridge propagation from east to west. Seafloor spreading initiated ˜20 Myr ago along a 200 km-long ridge portion located immediately west of the Owen fracture zone. A second 500 km-long ridge portion developed westward up to the Alula-Fartak transform fault before Chron 5D (17.5 Ma). Before Chron 5C (16.0 Ma), a third 700 km-long ridge portion was emplaced between the Alula-Fartak transform fault and the western end of the Gulf of Aden (45°E). Between 20 and 16 Ma, the Sheba Ridge propagated over a distance of 1400 km at an extremely fast average rate of 35 cm yr-1. The ridge propagation resulted from the Arabia-Somalia rigid plate rotation about a stationary pole. Since Chron 5C (16.0 Ma), the spreading rate of the Sheba Ridge decreased first rapidly until 10 Ma and then more slowly. The evolution of the AOC triple junction is marked by a change of configuration around 10 Ma, with the formation of a new Arabia-India plate boundary. Part of the Arabian plate was then transferred to the Indian plate.

  18. Far-infrared electroluminescence characteristics of an InGaP/InGaAs/Ge triple-junction solar cell under forward DC bias

    NASA Astrophysics Data System (ADS)

    Wenbo, Xiao; Xingdao, He; Yiqing, Gao; Zhimin, Zhang; Jiangtao, Liu

    2012-06-01

    The far-infrared electroluminescence characteristics of an InGaP/InGaAs/Ge solar cell are investigated under forward DC bias at room temperature in dark conditions. An electroluminescence viewgraph shows the clear device structures, and the electroluminescence intensity is shown to increases exponentially with bias voltage and linearly with bias current. The results can be interpreted using an equivalent circuit of a single ideal diode model for triple-junction solar cells. The good fit between the measured and calculated data proves the above conclusions. This work is of guiding significance for current solar cell testing and research.

  19. Comparative investigation of InGaP/InGaAs/Ge triple-junction solar cells using different Te-doped InGaP layers in tunnel junctions

    NASA Astrophysics Data System (ADS)

    Jung, Sang Hyun; Kim, Chang Zoo; Kim, Youngjo; Jun, Dong Hwan; Kang, Ho Kwan; Kim, Hogyoung

    2016-03-01

    Heavily tellurium (Te)-doped InGaP layers in tunnel junctions (TJs) grown by using metalorganic chemical vapor deposition (MOCVD) were investigated to improve the device performance of InGaP/InGaAs/Ge triple-junction solar cells. Three different doping techniques were employed to grow the Te-doped InGaP layers in the TJ; Te doping, Te and Si co-doping and Te pre-doping. Compared to other samples, the external quantum efficiency (EQE) profiles in the InGaP top cell were found to be higher for the sample with Te pre-doping. Under a concentrated light condition, higher fill factor (FF) and conversion efficiency were also observed for the sample with Te pre-doping. These indicate that the crystalline qualities of the upper TJ, composed of a p-GaAs/n-InGaP TJ, and the InGaP top cell were improved by using the Te pre-doping method.

  20. Investigation of GaInAs strain reducing layer combined with InAs quantum dots embedded in Ga(In)As subcell of triple junction GaInP/Ga(In)As/Ge solar cell.

    PubMed

    Li, Senlin; Bi, Jingfeng; Li, Mingyang; Yang, Meijia; Song, Minghui; Liu, Guanzhou; Xiong, Weiping; Li, Yang; Fang, Yanyan; Chen, Changqing; Lin, Guijiang; Chen, Wenjun; Wu, Chaoyu; Wang, Duxiang

    2015-01-01

    The InAs/GaAs quantum dots structure embedded in GaInP/Ga(In)As/Ge triple junction solar cell with and without Ga0.90In0.10As strain reducing layer was investigated. Conversion efficiency of 33.91% at 1,000 suns AM 1.5D with Ga0.90In0.10As strain reducing layer was demonstrated. A 1.19% improvement of the conversion efficiency was obtained via inserting the Ga0.90In0.10As strain reducing layer. The main contribution of this improvement was from the increase of the short-circuit current, which is caused by the reduction of the Shockley-Read-Hall recombination centers. Consequently, there was a decrease in open circuit voltage due to the lower thermal activation energy of confined carriers in Ga0.9In0.1As than GaAs and a reduction in the effective band gap of quantum dots. PMID:25852406

  1. Analysis of bias voltage dependent spectral response in Ga{sub 0.51}In{sub 0.49}P/Ga{sub 0.99}In{sub 0.01}As/Ge triple junction solar cell

    SciTech Connect

    Sogabe, Tomah Ogura, Akio; Okada, Yoshitaka

    2014-02-21

    Spectral response measurement plays great role in characterizing solar cell device because it directly reflects the efficiency by which the device converts the sunlight into an electrical current. Based on the spectral response results, the short circuit current of each subcell can be quantitatively determined. Although spectral response dependence on wavelength, i.e., the well-known external quantum efficiency (EQE), has been widely used in characterizing multijunction solar cell and has been well interpreted, detailed analysis of spectral response dependence on bias voltage (SR −V{sub bias}) has not been reported so far. In this work, we have performed experimental and numerical studies on the SR −V{sub bias} for Ga{sub 0.51}In{sub 0.49}P/Ga{sub 0.99}In{sub 0.01}As/Ge triple junction solar cell. Phenomenological description was given to clarify the mechanism of operation matching point variation in SR −V{sub bias} measurements. The profile of SR−V{sub bias} curve was explained in detail by solving the coupled two-diode current-voltage characteristic transcend formula for each subcell.

  2. Effects of ridge geometry on mantle dynamics in an oceanic triple junction region: Implications for the Azores Plateau

    NASA Astrophysics Data System (ADS)

    Georgen, Jennifer E.; Sankar, Ravi D.

    2010-09-01

    Plate boundary geometry can affect the nature of magmatism along a mid-ocean ridge. The Azores Plateau is located in a complex geological setting that includes a triple junction (TJ), an oblique and recently-formed ultra-slow-spreading ridge, a zone of diffuse seafloor deformation, a major fracture zone, and a postulated hotspot. The precise character of the hotspot is somewhat debated, as some lines of evidence indicate it may not be a classic deep-seated plume. However, seismic and gravity data suggest plateau crustal thicknesses of ˜ 8 km or more, implying some mechanism for excess melting. To assess the role of ridge geometry in creating the Azores Plateau, this study uses a finite element numerical model to isolate the effects of selected aspects of plate boundary configuration on mantle flow and melt production in a TJ kinematically similar to the Azores TJ. The model focuses on the slowest-spreading ridge in the TJ, analogous to the Terceira Rift. The effect of the varying ridge obliquity observed along the Terceira Rift is also assessed using an independent 1-D melting model. In general, relatively little melt production is predicted along the Terceira Rift analogue, except for regions closest to the TJ where the proximity of a faster-spreading ridge increases temperatures within the melting zone. In the 1-D melting model with mantle temperatures of 1350 °C, melt thicknesses of ˜ 2 km are calculated for the least oblique segments, while more oblique segments produce little to no melt. The presence of a long discontinuity (simulating the Gloria FZ) has little effect on mantle dynamics for axial distances < 350 km from the TJ, although crustal production is predicted to diminish to zero within ˜ 150 km of the discontinuity. When several ridge geometrical effects are combined (i.e., a TJ, time-limited spreading, a ridge discontinuity, and depressed spreading rates within ˜ 100 km of the TJ point), ˜ 2.5 km of variability in melt thickness can be produced

  3. Crust and Upper mantle heterogeneity in the Mendocino Triple Junction from teleseismic P-to-S scattered waves

    NASA Astrophysics Data System (ADS)

    Zhai, Y.; MacKenzie, J. M.; Levander, A.; Cao, A.; Porritt, R. W.; Allen, R. M.

    2010-12-01

    We have generated a 3D PdS receiver function (RF) common conversion point (CCP) stacked image volume to examine lithospheric structure in the Mendocino Triple Junction (MTJ) region. The image volume was made from 186 earthquakes recorded at 111 broadband stations of the Flexible Array Mendocino Experiment (FAME), the Berkeley Digital Seismic Network and the USArray Transportable Array. The data were depth mapped and laterally migrated incorporating using a layered earth model with 3D traveltime corrections determined from teleseismic P-and S-tomography models (Schmandt and Humphreys, 2010; Obrebski et al., 2010). The top and bottom of the subducting Gorda slab are identified by the top of oceanic crust/Moho and the lithosphere-asthenosphere Boundary (LAB), giving a thickness for the Gorda slab of ~ 40 km, comparable to that predicted by the half-space cooling model. The slab window in the transform regime has a complex structure, but its top can be traced continuously to the Gorda LAB, providing strong evidence that Coast Range volcanism results from subslab flow into the transform regime. The LAB is shallowest beneath the Clear Lake volcano field and the Lake Pillsbury pull-apart basin, the latter a site of active basalt diking previously imaged seismically (Levander et al. 1998, Hayes et al., 2006). Under the western part of the northern Great Valley, the Moho signal is absent, likely due to the hydration and serpentinization of the upper mantle during the subduction of the Gorda slab ~2Ma, as has been recognized further north in Cascadia (Bostock et al., 2002; Blakely et al., 2005). In the “mantle wedge” region where two Cascadia volcanoes are still active within ~ 200 years, the LAB is shallow, and the mantle wedge under Mt.’s Shasta and Lassen has a characteristic vertically and laterally heterogeneous signature. We have developed a 3D code for Generalized Radon Transform (GRT) inversion of PdS receiver functions based on the Born approximation. The code

  4. Catastrophic flank collapses and slumping in Pico Island during the last 130 kyr (Pico-Faial ridge, Azores Triple Junction)

    NASA Astrophysics Data System (ADS)

    Costa, A. C. G.; Hildenbrand, A.; Marques, F. O.; Sibrant, A. L. R.; Santos de Campos, A.

    2015-09-01

    The Pico Island constitutes the easternmost sub-aerial domain of a steep WNW-ESE volcanic ridge, which has developed within the Nubia-Eurasia diffuse plate boundary (Azores Triple Junction). The island comprises three volcanic systems, from older to younger: the Topo Volcano, the Fissural System, and the Pico Stratovolcano. From a high-resolution Digital Elevation Model (10 m), and new bathymetric, stratigraphic, structural, and high-precision K-Ar data, we reconstruct the main successive stages of growth and partial destruction of the island over the last 200 kyr. We especially concentrate on the central sector of the island, which has recorded gradual movements through slumping and catastrophic flank collapses since ca. 130 kyr. The remmants of the Topo Volcano are partly exposed on Pico's SE flank, and are here dated between 186 ± 5 and 115 ± 4 ka. Topo was significantly destroyed by N- and S-directed large-scale flank collapses between ca. 125 and 70 ka. On Pico's N flank, collapse seems to have removed all the unstable material, but in the S the collapse structure is composite, including a major flank collapse and a remnant slump complex that is still active. A first episode of deformation occurred between ca. 125 and 115 ka along the master fault of the slump. Between ca. 115 and 69 ka, most of the unstable material was removed by a major flank collapse, leaving behind a still considerable volume of unstable material that comprises the active slump. This first collapse was catastrophic and generated a large debris deposit recognized on the high-resolution bathymetry, with a minimum run-out of ca. 17 km. The scar was partially filled by volcanic products erupted from volcanic cones developed within the slump depression, and possibly also from the early WNW-ESE Fissural System. Subsequent deformation in the slump area affected in part the filling units, leading to the individualization of secondary curved faults. Younger volcanic products have gradually

  5. Amorphous silicon research: Phase II. Annual technical progress report, August 1, 1995--July 31, 1996

    SciTech Connect

    Guha, S

    1996-10-01

    This report describes the research performed during Phase II of a three-phase, three-year program under NREL Subcontract No. ZAN-4-13318-02. The research program is intended to expand, enhance and accelerate knowledge and capabilities for the development of high-performance, two-terminal multijunction hydrogenated amorphous silicon (a-Si:H) alloy modules. It is now well recognized that a multifunction, multibandgap approach has the potential of achieving the highest stable efficiency in a-Si:H alloy solar cells. In this approach, the bandgap of the materials of the component cell is varied in order to capture a wide spectrum of the solar photons. Significant progress has been made in the development of materials and cell design in the last few years, and a stable module efficiency of 10.2% has been demonstrated over one-square-foot area using a triple-junction approach in which the bottom two component cells use hydrogenated amorphous silicon-germanium (a-SiGe:H) alloy. In order to meet the Department of Energy goal of achievement of 12% stable module efficiency, it is necessary to make further improvements in each of the component cells. This has been the thrust of the current program.

  6. High-Efficiency Light-Emitting Diodes of Organometal Halide Perovskite Amorphous Nanoparticles.

    PubMed

    Xing, Jun; Yan, Fei; Zhao, Yawen; Chen, Shi; Yu, Huakang; Zhang, Qing; Zeng, Rongguang; Demir, Hilmi Volkan; Sun, Xiaowei; Huan, Alfred; Xiong, Qihua

    2016-07-26

    Organometal halide perovskite has recently emerged as a very promising family of materials with augmented performance in electronic and optoelectronic applications including photovoltaic devices, photodetectors, and light-emitting diodes. Herein, we propose and demonstrate facile solution synthesis of a series of colloidal organometal halide perovskite CH3NH3PbX3 (X = halides) nanoparticles with amorphous structure, which exhibit high quantum yield and tunable emission from ultraviolet to near-infrared. The growth mechanism and photoluminescence properties of the perovskite amorphous nanoparticles were studied in detail. A high-efficiency green-light-emitting diode based on amorphous CH3NH3PbBr3 nanoparticles was demonstrated. The perovskite amorphous nanoparticle-based light-emitting diode shows a maximum luminous efficiency of 11.49 cd/A, a power efficiency of 7.84 lm/W, and an external quantum efficiency of 3.8%, which is 3.5 times higher than that of the best colloidal perovskite quantum-dot-based light-emitting diodes previously reported. Our findings indicate the great potential of colloidal perovskite amorphous nanoparticles in light-emitting devices. PMID:27284993

  7. Flow at ice-divide triple junctions: 2. Three-dimensional views of isochrone architecture from ice-penetrating radar surveys

    NASA Astrophysics Data System (ADS)

    Hindmarsh, Richard C. A.; King, Edward C.; Mulvaney, Robert; Corr, Hugh F. J.; Hiess, Gisela; Gillet-Chaulet, Fabien

    2011-06-01

    Ground-based surveys of ice-divide triple junctions in two Antarctic ice rises, the Fletcher Promontory and Berkner Island, have been carried out using low-frequency ice-penetrating radars. These surveys have focused on understanding the internal layer architecture at and around the triple junctions, with a particular emphasis on understanding how the Raymond effect operates. A variety of features have been observed, including Raymond cupolas under the junctions, bump stacks of varying amplitude with distance from the divide, double bumps, crooked stacks implying divide motion, and the presence of ridges containing weak and strong bump stacks. It was generally not possible to elucidate the three-dimensional structure by correlation of pick crossovers, so instead a least squares cross-correlation technique was used which computes nominal age surfaces using radial basis function interpolation. Double bumps are absent from the central cupola of Fletcher Promontory, permitting us to infer that the ice here has thinned by around 500 m in the past 5000 years. Estimates of the age scale suggest that there will be recoverable Eemian ice. A technique for inferring the velocity profile at divides using layer traces and assumed velocities in the flanks is presented.

  8. The boundary between the eastern and western domains of the Pyrenean Orogen: a Cenozoic triple junction zone in Iberia?

    NASA Astrophysics Data System (ADS)

    Tavani, S.

    2012-04-01

    occurred due to the penetration of the NW-SE-striking intraplate right-lateral transpressive system of the Iberian Chain into the Cantabrian Domain of the Pyrenean Orogen. Cenozoic right-lateral reactivation of the Ubierna Fault System, in fact, is part of a NW-SE striking intraplate strike-slip transpressive system, which to the south-east includes the Iberian Chain until the Mediterranean Sea and that, in the western termination of the Ubierna Fault System, branches off into three main splay faults, which are the Ventaniella and Leon faults, and the Duero frontal thrust. Taking into account the role of this Cenozoic transpressive system allows to drastically reduce the gap between plate kinematic reconstructions and geological evidences. This implies that, despite the limited amount of displacement, the Iberian Chain and the Ubierna-Ventaniella systems must be elevated to the rank of microplate boundary, which divided two sectors of the Iberian Plate. Accordingly, the intersection between this system and the Pyrenean Orogen, which occurs in the CTA, must be regarded as a triple junction zone.

  9. High efficiency multijunction amorphous silicon alloy-based solar cells and modules

    SciTech Connect

    Guha, S.; Yang, J.; Banerjeee, A.; Glatfelter, T.; Hoffman, K.; Xu, X. )

    1994-06-30

    We have achieved initial efficiency of 11.4% as confirmed by National Renewable Energy Laboratory (NREL) on a multijunction amorphous silicon alloy photovoltaic module of one-square-foot-area. [bold This] [bold is] [bold the] [bold highest] [bold initial] [bold efficiency] [bold confirmed] [bold by] [bold NREL] [bold for] [bold any] [bold thin] [bold film] [bold photovoltaic] [bold module]. After light soaking for 1000 hours at 50 [degree]C under one-sun illumination, a module with initial efficiency of 11.1% shows a stabilized efficiency of 9.5%. Key factors that led to this high performance are discussed.

  10. Highly efficient ultrathin-film amorphous silicon solar cells on top of imprinted periodic nanodot arrays

    SciTech Connect

    Yan, Wensheng Gu, Min; Tao, Zhikuo; Ong, Thiam Min Brian

    2015-03-02

    The addressing of the light absorption and conversion efficiency is critical to the ultrathin-film hydrogenated amorphous silicon (a-Si:H) solar cells. We systematically investigate ultrathin a-Si:H solar cells with a 100 nm absorber on top of imprinted hexagonal nanodot arrays. Experimental evidences are demonstrated for not only notable silver nanodot arrays but also lower-cost ITO and Al:ZnO nanodot arrays. The measured external quantum efficiency is explained by the simulation results. The J{sub sc} values are 12.1, 13.0, and 14.3 mA/cm{sup 2} and efficiencies are 6.6%, 7.5%, and 8.3% for ITO, Al:ZnO, and silver nanodot arrays, respectively. Simulated optical absorption distribution shows high light trapping within amorphous silicon layer.

  11. Results of some initial space qualification testing on triple junction a-Si and CuInSe2 thin film solar cells

    NASA Technical Reports Server (NTRS)

    Mueller, Robert L.; Anspaugh, Bruce E.

    1993-01-01

    A series of environmental tests were completed on one type of triple junction a-Si and two types of CuInSe2 thin film solar cells. The environmental tests include electron irradiation at energies of 0.7, 1.0, and 2.0 MeV, proton irradiation at energies of 0.115, 0.24, 0.3, 0.5, 1.0, and 3.0 MeV, post-irradiation annealing at temperatures between 20 C and 60 C, long term exposure to air mass zero (AM0) photons, measurement of the cells as a function of temperature and illumination intensity, and contact pull strength tests. As expected, the cells are very resistant to electron and proton irradiation. However, when a selected cell type is exposed to low energy protons designed to penetrate to the junction region, there is evidence of more significant damage. A significant amount of recovery was observed after annealing in several of the cells. However, it is not permanent and durable, but merely a temporary restoration, later nullified with additional irradiation. Contact pull strengths measured on the triple junction a-Si cells averaged 667 grams, and pull strengths measured on the Boeing CuInSe2 cells averaged 880 grams. Significant degradation of all cell types was observed after exposure to a 580 hour photon degradation test, regardless of whether the cells had been unirradiated or irradiated (electrons or protons). Although one cell from one manufacturer lost approximately 60 percent of its power after the photon test, several other cells from this manufacturer did not degrade at all.

  12. A Review on Forearc Ophiolite Obduction, Adakite-Like Generation, and Slab Window Development at the Chile Triple Junction Area: Uniformitarian Framework for Spreading-Ridge Subduction

    NASA Astrophysics Data System (ADS)

    Bourgois, Jacques; Lagabrielle, Yves; Martin, Hervé; Dyment, Jérôme; Frutos, Jose; Cisternas, Maria Eugenia

    2016-05-01

    This paper aggregates the main basic data acquired along the Chile Triple Junction (CTJ) area (45°-48°S), where an active spreading center is presently subducting beneath the Andean continental margin. Updated sea-floor kinematics associated with a comprehensive review of geologic, geochemical, and geophysical data provide new constraints on the geodynamics of this puzzling area. We discuss: (1) the emplacement mode for the Pleistocene Taitao Ridge and the Pliocene Taitao Peninsula ophiolite bodies. (2) The occurrence of these ophiolitic complexes in association with five adakite-like plutonic and volcanic centers of similar ages at the same restricted locations. (3) The inferences from the co-occurrence of these sub-coeval rocks originating from the same subducting oceanic lithosphere evolving through drastically different temperature-pressure (P-T) path: low-grade greenschist facies overprint and amphibolite-eclogite transition, respectively. (4) The evidences that document ridge-jump events and associated microplate individualization during subduction of the SCR1 and SCR-1 segments: the Chonos and Cabo Elena microplates, respectively. The ridge-jump process associated with the occurrence of several closely spaced transform faults entering subduction is controlling slab fragmentation, ophiolite emplacement, and adakite-like production and location in the CTJ area. Kinematic inconsistencies in the development of the Patagonia slab window document an 11- km westward jump for the SCR-1 spreading segment at ~6.5-to-6.8 Ma. The SCR-1 spreading center is relocated beneath the North Patagonia Icefield (NPI). We argue that the deep-seated difference in the dynamically sustained origin of the high reliefs of the North and South Patagonia Icefield (NPI and SPI) is asthenospheric convection and slab melting, respectively. The Chile Triple Junction area provides the basic constraints to define the basic signatures for spreading-ridge subduction beneath an Andean

  13. Research on defects and transport in amorphous-silicon-based semiconductors. Final subcontract report, 20 February 1991--19 April 1994

    SciTech Connect

    Schiff, E.A.; Antoniadis, H.; Gu, Q.; Lee, J.K.; Wang, Q.; Zafar, S.

    1994-09-01

    This report describes work on three individual tasks as follows. (1) Electron and hole drift measurements in a-Si{sub 1-x}Ge{sub x}:H and a-Si{sub 1-x}C{sub x}:H p-i-n solar cells. Multijunction solar cells incorporating modified band gap a-Si:H in a triple-junction structure are generally viewed as the most promising avenue for achieving an amorphous silicon-based solar call with 15% stabilized conversion efficiency. The specific objective of this task was to document the mobilities and deep-trapping mobility-lifetime products for electrons and holes in a-Si{sub 1-x}Ge{sub x}:H and a-Si{sub 1-x}C{sub x}:H alloys materials. (2) Electroabsorption measurements and built-in potential (V{sub bi}) in solar cells. V{sub bi} in a p-i-n solar call may be limiting the open-circuit voltage (V{sub oc}) in wide-band-gap cells (E{sub g} > 1.8 eV) currently under investigation as the top cell for 15% triple junction devices. The research addressed four issues that need to be resolved before the method can yield an error less than 0.1 V for V{sub bi}. The details are presented in this report. (3) Defect relaxation and Shockley-Read kinetics in a-Si:H. Quantitative modeling of solar cells is usually based on Shockley-Read kinetics.`` An important assumption of this approach is that the rate of emission of a photocarrier trapped on a defect is independent of quasi-Fermi level location.

  14. Improved conversion efficiency of amorphous Si solar cells using a mesoporous ZnO pattern

    PubMed Central

    2014-01-01

    To provide a front transparent electrode for use in highly efficient hydrogenated amorphous silicon (a-Si:H) thin-film solar cells, porous flat layer and micro-patterns of zinc oxide (ZnO) nanoparticle (NP) layers were prepared through ultraviolet nanoimprint lithography (UV-NIL) and deposited on Al-doped ZnO (AZO) layers. Through this, it was found that a porous micro-pattern of ZnO NPs dispersed in resin can optimize the light-trapping pattern, with the efficiency of solar cells based on patterned or flat mesoporous ZnO layers increased by 27% and 12%, respectively. PMID:25276101

  15. Efficient Crystalline Si Solar Cell with Amorphous/Crystalline Silicon Heterojunction as Back Contact: Preprint

    SciTech Connect

    Nemeth, B.; Wang, Q.; Shan, W.

    2012-06-01

    We study an amorphous/crystalline silicon heterojunction (Si HJ) as a back contact in industrial standard p-type five-inch pseudo-square wafer to replace Al back surface field (BSF) contact. The best efficiency in this study is over 17% with open-circuit (Voc) of 0.623 V, which is very similar to the control cell with Al BSF. We found that Voc has not been improved with the heterojunction structure in the back. The typical minority carrier lifetime of these wafers is on the order of 10 us. We also found that the doping levels of p-layer affect the FF due to conductivity and band gap shifting, and an optimized layer is identified. We conclude that an amorphous/crystalline silicon heterojunction can be a very promising structure to replace Al BSF back contact.

  16. Carbon nanotube-amorphous silicon hybrid solar cell with improved conversion efficiency.

    PubMed

    Funde, Adinath M; Nasibulin, Albert G; Syed, Hashmi Gufran; Anisimov, Anton S; Tsapenko, Alexey; Lund, Peter; Santos, J D; Torres, I; Gandía, J J; Cárabe, J; Rozenberg, A D; Levitsky, Igor A

    2016-05-01

    We report a hybrid solar cell based on single walled carbon nanotubes (SWNTs) interfaced with amorphous silicon (a-Si). The high quality carbon nanotube network was dry transferred onto intrinsic a-Si forming Schottky junction for metallic SWNT bundles and heterojunctions for semiconducting SWNT bundles. The nanotube chemical doping and a-Si surface treatment minimized the hysteresis effect in current-voltage characteristics allowing an increase in the conversion efficiency to 1.5% under an air mass 1.5 solar spectrum simulator. We demonstrated that the thin SWNT film is able to replace a simultaneously p-doped a-Si layer and transparent conductive electrode in conventional amorphous silicon thin film photovoltaics. PMID:27005494

  17. Carbon nanotube-amorphous silicon hybrid solar cell with improved conversion efficiency

    NASA Astrophysics Data System (ADS)

    Funde, Adinath M.; Nasibulin, Albert G.; Gufran Syed, Hashmi; Anisimov, Anton S.; Tsapenko, Alexey; Lund, Peter; Santos, J. D.; Torres, I.; Gandía, J. J.; Cárabe, J.; Rozenberg, A. D.; Levitsky, Igor A.

    2016-05-01

    We report a hybrid solar cell based on single walled carbon nanotubes (SWNTs) interfaced with amorphous silicon (a-Si). The high quality carbon nanotube network was dry transferred onto intrinsic a-Si forming Schottky junction for metallic SWNT bundles and heterojunctions for semiconducting SWNT bundles. The nanotube chemical doping and a-Si surface treatment minimized the hysteresis effect in current-voltage characteristics allowing an increase in the conversion efficiency to 1.5% under an air mass 1.5 solar spectrum simulator. We demonstrated that the thin SWNT film is able to replace a simultaneously p-doped a-Si layer and transparent conductive electrode in conventional amorphous silicon thin film photovoltaics.

  18. The Karoo triple junction questioned : Evidence from 40Ar/39Ar Jurassic and Proterozoïc ages and geochemistry of the Okavango dyke swarm (Botswana).

    NASA Astrophysics Data System (ADS)

    Jourdan, F.; Féraud, G.; Bertrand, H.; Kampunzu, A. B.; Tshoso, G.; Le Gall, B.; Tiercelin, J. J.

    2003-04-01

    The lower Jurassic Karoo-Ferrar magmatism represents one of the most important Phanerozoic continental flood basalt (CFB) provinces. Karoo CFB is dominated by tholeiitic traps and apparently radiating giant dyke swarms covering altogether ca 3x106 km2. This study focuses on the giant N110° oriented Okavango dyke swarm (ODS) stretching over a distance of 1500 km through Botswana. This dyke swarm represents the main arm of the so-called Karoo triple junction which is generally considered as a key marker linking the Karoo magmatism to a starting mantle plume impact (Campbell and Griffiths, 1990). ODS dolerites yield twelve reliable plagioclase 40Ar/39Ar plateau (and mini-plateau) ages ranging from 178.3 +-1.1 (2 sigma) to 179.3 +-1.2 Ma (Le Gall et al, 2002 and unpublished data). The distribution of the ages along a narrow gaussian curve suggests a short period of magmatic activity centered around 178.9 Ma. In addition, small clusters of plagioclase separated from twenty-five other dykes and measured by total fusion, gave either Karoo or Proterozoïc ages. The Proterozoïc rocks range from 758.2 +-6.6 Ma and 1223.8 +-10.0 Ma (integrated ages) and, although petrographically indistinguishable in some cases, they display clear geochemical differences (e.g. TiO2<2%, Ti/Y<400) compared to the Karoo high-Ti ODS (TiO2>2%, Ti/Y>400). Geochemical data combined with available Ar/Ar dates allowed us to identify the two groups within a total set of seventy-eight dykes investigated: about 15 % of the bulk ODS dykes were emplaced during the Proterozoïc and, thus, the Jurassic Karoo dykes were emplaced along reactivated Proterozoïc structures. The validity of the Karoo triple junction-plume model, should therefore be revisited. Although available data on Proterozoïc dykes along the ODS are not precise enough to assess their exact emplacement age, they indicate that most of the Proterozoïc dykes were emplaced between 900 and 1100 Ma. This age range is the same as dating commonly

  19. The Relationships of Plate Triple-junction Evolution, Trench-Arc Lengthening, Boninite Generation, and SSZ Spreading Centers to Ophiolite Formation, High-Temperature Soles, and Obduction

    NASA Astrophysics Data System (ADS)

    Casey, J.; Dewey, J. F.

    2014-12-01

    A review of modern-day island arcs, the locations of boninite eruptions, the conditions necessary for hot upper plate spreading, potential regions of shallow SSZ flux melting, and formation of high-temperature metamorphic soles along the subduction channels indicates that many future, recent and ancient large slab ophiolite obduction events can be related to triple junctions that link SSZ spreading centers with trenches. These subduction systems leading to large slab ophiolite obduction events typically face stable continental margins. Boninitic melt generation requires hydrous melting of refractory mantle peridotite under an extremely high-temperature and low-pressure condition. This condition is generally explained by the addition of slab-derived fluids into a hot young oceanic mantle asthenosphere and lithosphere, which previously likely experienced melt extraction. Metamorphic conditions associated with metamorphic soles formation likewise require a hot upper plate lithosphere that, based on sole protolith, geochronologic and thermochronologic data, rapidly heats and then refrigerates and decompresses MORB-OIB type subcreted lithosphere. Numerous examples of present-day and recent SSZ spreading centers that link with two trenches or a trench and transform are considered ideal sites for ophiolite and boninite generation. The SZZ fore-arc spreading centers that link to the trench lines and triple junctions at the front of the arc may also continue towards the arc and back arc, creating no distinction between fore-arc and back-arc spreading episodes or to the transform-linked spreading centers from fore-arc to back arc. These SSZ spreading centers, which may be transiently produced during arc evolution over short or protracted time periods, act to open gaps in the arc massif and lengthen the trench, fore-arc and the arc crustal massif. They lead to an evolving arc magmatic front that begins in the infant fore-arc where ophiolite generation occurs at, near or in

  20. A generic concept to overcome bandgap limitations for designing highly efficient multi-junction photovoltaic cells

    PubMed Central

    Guo, Fei; Li, Ning; Fecher, Frank W.; Gasparini, Nicola; Quiroz, Cesar Omar Ramirez; Bronnbauer, Carina; Hou, Yi; Radmilović, Vuk V.; Radmilović, Velimir R.; Spiecker, Erdmann; Forberich, Karen; Brabec, Christoph J.

    2015-01-01

    The multi-junction concept is the most relevant approach to overcome the Shockley–Queisser limit for single-junction photovoltaic cells. The record efficiencies of several types of solar technologies are held by series-connected tandem configurations. However, the stringent current-matching criterion presents primarily a material challenge and permanently requires developing and processing novel semiconductors with desired bandgaps and thicknesses. Here we report a generic concept to alleviate this limitation. By integrating series- and parallel-interconnections into a triple-junction configuration, we find significantly relaxed material selection and current-matching constraints. To illustrate the versatile applicability of the proposed triple-junction concept, organic and organic-inorganic hybrid triple-junction solar cells are constructed by printing methods. High fill factors up to 68% without resistive losses are achieved for both organic and hybrid triple-junction devices. Series/parallel triple-junction cells with organic, as well as perovskite-based subcells may become a key technology to further advance the efficiency roadmap of the existing photovoltaic technologies. PMID:26177808

  1. A generic concept to overcome bandgap limitations for designing highly efficient multi-junction photovoltaic cells.

    PubMed

    Guo, Fei; Li, Ning; Fecher, Frank W; Gasparini, Nicola; Ramirez Quiroz, Cesar Omar; Bronnbauer, Carina; Hou, Yi; Radmilović, Vuk V; Radmilović, Velimir R; Spiecker, Erdmann; Forberich, Karen; Brabec, Christoph J

    2015-01-01

    The multi-junction concept is the most relevant approach to overcome the Shockley-Queisser limit for single-junction photovoltaic cells. The record efficiencies of several types of solar technologies are held by series-connected tandem configurations. However, the stringent current-matching criterion presents primarily a material challenge and permanently requires developing and processing novel semiconductors with desired bandgaps and thicknesses. Here we report a generic concept to alleviate this limitation. By integrating series- and parallel-interconnections into a triple-junction configuration, we find significantly relaxed material selection and current-matching constraints. To illustrate the versatile applicability of the proposed triple-junction concept, organic and organic-inorganic hybrid triple-junction solar cells are constructed by printing methods. High fill factors up to 68% without resistive losses are achieved for both organic and hybrid triple-junction devices. Series/parallel triple-junction cells with organic, as well as perovskite-based subcells may become a key technology to further advance the efficiency roadmap of the existing photovoltaic technologies. PMID:26177808

  2. A generic concept to overcome bandgap limitations for designing highly efficient multi-junction photovoltaic cells

    NASA Astrophysics Data System (ADS)

    Guo, Fei; Li, Ning; Fecher, Frank W.; Gasparini, Nicola; Quiroz, Cesar Omar Ramirez; Bronnbauer, Carina; Hou, Yi; Radmilović, Vuk V.; Radmilović, Velimir R.; Spiecker, Erdmann; Forberich, Karen; Brabec, Christoph J.

    2015-07-01

    The multi-junction concept is the most relevant approach to overcome the Shockley-Queisser limit for single-junction photovoltaic cells. The record efficiencies of several types of solar technologies are held by series-connected tandem configurations. However, the stringent current-matching criterion presents primarily a material challenge and permanently requires developing and processing novel semiconductors with desired bandgaps and thicknesses. Here we report a generic concept to alleviate this limitation. By integrating series- and parallel-interconnections into a triple-junction configuration, we find significantly relaxed material selection and current-matching constraints. To illustrate the versatile applicability of the proposed triple-junction concept, organic and organic-inorganic hybrid triple-junction solar cells are constructed by printing methods. High fill factors up to 68% without resistive losses are achieved for both organic and hybrid triple-junction devices. Series/parallel triple-junction cells with organic, as well as perovskite-based subcells may become a key technology to further advance the efficiency roadmap of the existing photovoltaic technologies.

  3. Light-induced Voc increase and decrease in high-efficiency amorphous silicon solar cells

    NASA Astrophysics Data System (ADS)

    Stuckelberger, M.; Riesen, Y.; Despeisse, M.; Schüttauf, J.-W.; Haug, F.-J.; Ballif, C.

    2014-09-01

    High-efficiency amorphous silicon (a-Si:H) solar cells were deposited with different thicknesses of the p-type amorphous silicon carbide layer on substrates of varying roughness. We observed a light-induced open-circuit voltage (Voc) increase upon light soaking for thin p-layers, but a decrease for thick p-layers. Further, the Voc increase is enhanced with increasing substrate roughness. After correction of the p-layer thickness for the increased surface area of rough substrates, we can exclude varying the effective p-layer thickness as the cause of the substrate roughness dependence. Instead, we explain the observations by an increase of the dangling-bond density in both the p-layer—causing a Voc increase—and in the intrinsic absorber layer, causing a Voc decrease. We present a mechanism for the light-induced increase and decrease, justified by the investigation of light-induced changes of the p-layer and supported by Advanced Semiconductor Analysis simulation. We conclude that a shift of the electron quasi-Fermi level towards the conduction band is the reason for the observed Voc enhancements, and poor amorphous silicon quality on rough substrates enhances this effect.

  4. Broadband antireflection sub-wavelength structure of InGaP/InGaAs/Ge triple junction solar cell with composition-graded SiNx

    NASA Astrophysics Data System (ADS)

    Chung, Chen-Chen; Lo, Hsiao-Chieh; Lin, Yen-Ku; Yu, Hung-Wei; Tinh Tran, Binh; Lin, Kung-Liang; Chen, Yung Chang; Quan, Nguyen-Hong; Chang, Edward Yi; Tseng, Yuan-Chieh

    2015-05-01

    This work reports a fabrication strategy to improve the antireflective ability of a InGaP/GaAs/Ge triple-junction solar cell, by combining a nano-templating technique and a chemical-synthesis approach. SiH4 and N2 were used as ammonia-free reaction gases in a plasma-enhanced chemical vapor deposition (PECVD) to prepare Si3N4 as an original antireflective coating (ARC) layer with better chemical stability. Composition-graded SiNx was successfully integrated with sub-wavelength structure by modulating SiH4/N2 ratio during PECVD deposition, and followed by a controllable gold-nanoparticle masking technique on top of the solar cell. Finite-difference time-domain solution was employed to simulate and optimize the aspect-ratio of the ARC, under the condition of variable refractive index over a broad wavelength window, and followed by the masking technique to obtain the desired ARC dimension. This enabled a low light reflectance (<10%) over a broad spectral bandwidth (300-1800 nm) for the solar cell with excellent stability, because of the triple advantages of structural optimization, better chemical stability and graded refractive index of the ARC. The solar cell’s performance was tested and showed great competitiveness to those of forefront studies, suggesting the feasibility of the proposed technology.

  5. Isotope systematics of Li, Sr, Nd, and volatiles in Indian Ocean MORBs of the Rodrigues Triple Junction: Constraints on the origin of the DUPAL anomaly

    NASA Astrophysics Data System (ADS)

    Nishio, Yoshiro; Nakai, Shun'ichi; Ishii, Teruaki; Sano, Yuji

    2007-02-01

    The DUPAL anomaly, a radiogenic isotope anomaly discovered in the Indian Ocean mantle, has been interpreted as due to a large-scale mantle heterogeneity. To provide new constraints on the DUPAL origin, we analyzed isotope ratios of Li, Sr, and Nd in fresh N-MORB glasses recovered from the Rodrigues Triple Junction in the Indian Ocean, and from the North Atlantic. The Li isotopic compositions of the Indian Ocean DUPAL N-MORBs were comparable to those of the North Atlantic non-DUPAL N-MORBs. The source of the DUPAL signature in Indian Ocean MORBs and the E-MORB-type enriched mantle source have quite different Li isotopic compositions. The 143Nd/ 144Nd values of both sources are significantly lower than those of the North Atlantic N-MORBs. The δ 7Li values of most oceanic island basalts with similar low 143Nd/ 144Nd signatures are also higher than those of the North Atlantic N-MORBs, except for several Koolau lavas. The Li isotope results support the recent proposal that significant amounts of recycled lower continental crust might produce the radiogenic isotope signatures of the Indian Ocean DUPAL source.

  6. Room-temperature efficient light detection by amorphous Ge quantum wells

    PubMed Central

    2013-01-01

    In this work, ultrathin amorphous Ge films (2 to 30 nm in thickness) embedded in SiO2 layers were grown by magnetron sputtering and employed as proficient light sensitizer in photodetector devices. A noteworthy modification of the visible photon absorption is evidenced due to quantum confinement effects which cause both a blueshift (from 0.8 to 1.8 eV) in the bandgap and an enhancement (up to three times) in the optical oscillator strength of confined carriers. The reported quantum confinement effects have been exploited to enhance light detection by Ge quantum wells, as demonstrated by photodetectors with an internal quantum efficiency of 70%. PMID:23496870

  7. Optical Modulation of the Diffraction Efficiency in an Indoline Azobenzene/Amorphous Polycarbonate Film.

    PubMed

    Williams, G V M; Do, My T T; Middleton, A; Raymond, S G; Bhuiyan, M D H; Kay, A J

    2016-12-01

    We have made a diffraction grating in an indoline azobenzene/amorphous polycarbonate film by two-beam interference at 532 nm that periodically photodegrades the indoline azobenzene dye. Subsequent illumination of the film with 532-nm light into the trans-isomer band leads to trans-cis isomerization in the indoline azobenzene dye and results in a decrease in the trans-isomer band absorption coefficient. This causes the diffraction efficiency to decrease when probed at 655 nm. The diffraction efficiency returns to its original value when the 532-nm light is blocked by thermal relaxation from the indoline azobenzene cis-isomer to the trans-isomer. Thus, we have been able to optically modulate the diffraction efficiency in a thin film diffraction grating. PMID:27416904

  8. Optical Modulation of the Diffraction Efficiency in an Indoline Azobenzene/Amorphous Polycarbonate Film

    NASA Astrophysics Data System (ADS)

    Williams, G. V. M.; Do, My T. T.; Middleton, A.; Raymond, S. G.; Bhuiyan, M. D. H.; Kay, A. J.

    2016-07-01

    We have made a diffraction grating in an indoline azobenzene/amorphous polycarbonate film by two-beam interference at 532 nm that periodically photodegrades the indoline azobenzene dye. Subsequent illumination of the film with 532-nm light into the trans-isomer band leads to trans- cis isomerization in the indoline azobenzene dye and results in a decrease in the trans-isomer band absorption coefficient. This causes the diffraction efficiency to decrease when probed at 655 nm. The diffraction efficiency returns to its original value when the 532-nm light is blocked by thermal relaxation from the indoline azobenzene cis-isomer to the trans-isomer. Thus, we have been able to optically modulate the diffraction efficiency in a thin film diffraction grating.

  9. High-Efficiency Amorphous Silicon and Nanocrystalline Silicon-Based Solar Cells and Modules: Final Technical Progress Report, 30 January 2006 - 29 January 2008

    SciTech Connect

    Guha, S.; Yang, J.

    2008-05-01

    United Solar Ovonic successfully used its spectrum-splitting a-Si:H/a-SiGe:H/a-SiGe:H triple-junction structure in their manufacturing plants, achieving a manufacturing capacity of 118 MW in 2007, and set up a very aggressive expansion plan to achieve grid parity.

  10. Continuous roll-to-roll amorphous silicon photovoltaic manufacturing technology. Semiannual subcontract report, 1 April 1993--30 September 1993

    SciTech Connect

    Izu, M.

    1994-06-01

    This report describes work for this reporting period under a 3-year program to advance Energy Conversion Device`s (ECD) roll-to-roll, triple-junction photovoltaic (PV) manufacturing technologies, to reduce the module production costs, to increase the stabilized module performance, and to expand commercial production capacity utilizing ECD technology. The specific 3-year goal is to develop advanced large-scale manufacturing technology incorporating ECD`s earlier research advances with the capability of producing modules with stable 11% efficiency at a cost of approximately $1.00 per peak watt. Major accomplishments during this reporting period include (1) the design, construction. amd testomg of a continuous roll-to-roll multipurpose amorphous silicon alloy solar cell deposition machine that incorporates improvements necessary to obtain higher efficiency solar cells; (2) development of a photothermal deflection spectroscopy (PDS) technique for evaluating back-reflector systems; (3) the development of an improved textured Ag/ZnO back-reflector system demonstrating 25% gain in J{sub sc} over previous textured Al back-reflector systems; and (4) the design of a serpentine web continuous roll-to-roll deposition chamber.

  11. A brief Oligocene period of flood volcanism in Yemen: Implications for the duration and rate of continental flood volcanism at the Afro-Arabian triple junction

    USGS Publications Warehouse

    Baker, J.; Snee, L.; Menzies, M.

    1996-01-01

    -Gulf of Aden rifting. The sequence of events - surface uplift (?), flood magmatism and subsequent upper crustal extension - in Yemen is consistent with the involvement of a mantle plume at the Afro-Arabian triple junction. However, the overall eruption rate for this flood volcanic province is only 0.03 km3/yr, much slower than that postulated for other plume-related provinces such as the Deccan or Siberian Traps, but perhaps comparable to the Parana??-Etendeka province, which also contains significant amounts of rhyolitic volcanic products like those of Yemen-Ethiopia. The highly variable eruption rates in individual provinces must reflect the very different character of individual plumes, or the control of lithospheric structure and plate tectonic stresses on the surface manifestations of plumes. The long duration of CFV and large amounts of rhyolitic volcanism at the Afro-Arabian triple junction may be attributed to the relatively slow separation of the African and Arabian plates compared with, for example, the rifting of India and the Deccan Traps.

  12. Morphology and growth history of Delgada Fan: implications for the Neogene evolution of Point Arena Basin and the Mendocino Triple Junction

    USGS Publications Warehouse

    Drake, D.E.; Cacchione, D.A.; Gardner, J.V.; McCulloch, D.S.; Masson, D.

    1989-01-01

    Long-range side scan (GLORIA) sonographs and seismic reflection data acquired during a survey of the western US Exclusive Economic Zone in 1984, coupled with information from Deep Sea Drilling Project sites, provide new insights into the growth and evolution of the Delgada Fan. Construction of the fan commenced in the latest Miocene (~6 Ma) following the filling of the Neogene Point Arena Basin. The large size of the fan is incompatible with the small present-day supply of sediment to the canyon system. The GLORIA data show the Delgada Fan to be a hybrid-type fan, exhibiting characteristics of both elongate and radial fans. The morphology and volume of the fan, along with evidence for a decline in accumulation rates on the lower fan during the Quaternary period, suggest that the fan experienced an early growth phase (latest Miocene and Pliocene) characterized by relatively rapid progradation of elongate fan lobes followed by a period (Quaternary) of slower growth that has featured a shift of depocenters to sites closer to the canyons and a transition to distributary channels bordered by less prominent levees and overbank deposits. We examine the growth of Delgada Fan in relation to the Neogene evolution of the North American-Pacific plate boundary using a series of paleogeographic reconstructions based on recently published time displacement histories of the Mendocino triple junction (MTJ), the San Andreas fault (SAF), and the Pacific plate, upon which the fan rests. The time displacement curves for the SAF and the MTJ suggest that the MTJ and Mendocino Fracture Zone overtook and passed Point Arena Basin at about 10 Ma when the basin lay immediately southwest of the present San Francisco Bay area. We suggest that the MTJ joined the SAF at approximately that time and location, thus making the SAF the master fault in the transform system. -from Authors

  13. Geology of the Eel River basin and adjacent region: Implications for late Cenozoic tectonics of the southern Cascadia subduction zone and Mendocino triple junction

    SciTech Connect

    Clarke, S.H. Jr. )

    1992-02-01

    Two upper Cenozoic depositional sequences of principally marine strata about 4,000 m thick overlie accreted basement terranes of the Central and Coastal belts of the Franciscan Complex in the onshore-offshore Eel River basin of northwestern California. The older depositional sequence is early to middle Miocene in age and represents slope basin and slope-blanket deposition, whereas the younger sequence, later Miocene to middle Pleistocene in age, consists largely of forearc basin deposits. Youthful tectonic activity related to Gorda-North American plate convergence indicates an active Cascadia subduction zone and strong partial coupling between these plates. Structures of the northeastern margin of the Eel River basin are principally north-northwest-trending, east-northeast-dipping thrust and reverse faults that form imbricate thrust fans. The Coastal belt fault, the early Tertiary accretionary suture between the Franciscan Central and Coastal belts, can be traced from Arcata Bay northward offshore to the southern Oregon border. It is tentatively extended farther northward based on aeromagnetic data to an offshore position west of Cape Blanco. Thereafter, it may coincide with the offshore Fulmar fault. The Cascadia subduction zone (CSZ) does not join the Mendocino transform fault at the commonly depicted offshore location of the Mendocino triple junction (MTJ). Instead, the CSZ extends southeastward around the southern Eel River basin and shoreward along Mendocino Canyon to join the Petrolia shear zone. Similarly, the Mendocino fault may extend shoreward via Mattole Canyon and join the Cooskie shear zone. These two shear zones intersect onshore north of the King Range, and the area of their intersection is the probable location of the MTJ.

  14. Efficient nanorod-based amorphous silicon solar cells with advanced light trapping

    NASA Astrophysics Data System (ADS)

    Kuang, Y.; van Lare, M. C.; Veldhuizen, L. W.; Polman, A.; Rath, J. K.; Schropp, R. E. I.

    2015-11-01

    We present a simple, low-cost, and scalable approach for the fabrication of efficient nanorod-based solar cells. Templates with arrays of self-assembled ZnO nanorods with tunable morphology are synthesized by chemical bath deposition using a low process temperature at 80 °C. The nanorod templates are conformally coated with hydrogenated amorphous silicon light absorber layers of 100 nm and 200 nm thickness. An initial efficiency of up to 9.0% is achieved for the optimized design. External quantum efficiency measurements on the nanorod cells show a substantial photocurrent enhancement both in the red and the blue parts of the solar spectrum. Key insights in the light trapping mechanisms in these arrays are obtained via a combination of three-dimensional finite-difference time-domain simulations, optical absorption, and external quantum efficiency measurements. Front surface patterns enhance the light incoupling in the blue, while rear side patterns lead to enhanced light trapping in the red. The red response in the nanorod cells is limited by absorption in the patterned Ag back contact. With these findings, we develop and experimentally realize a further advanced design with patterned front and back sides while keeping the Ag reflector flat, showing significantly enhanced scattering from the back reflector with reduced parasitic absorption in the Ag and thus higher photocurrent generation. Many of the findings in this work can serve to provide insights for further optimization of nanostructures for thin-film solar cells in a broad range of materials.

  15. Large-area, triple-junction a-Si alloy production scale-up. Semiannual subcontract report, 17 March 1993--18 September 1993

    SciTech Connect

    Oswald, R.; O`Dowd, J.; Ashenfelter, W.

    1994-03-01

    This report describes work to improve the efficiency of large-area, multi-junction amorphous silicon (a-Si) alloy modules. Equipment capable of producing modules up to 0.74 m{sup 2} in area is on line and process development has begun. Preliminary cost analysis/reduction has begun to ensure that these development efforts will result in a commercialization of the large-area technology. The approach was to transfer the high-efficiency multi-junction technology from R&D into the manufacturing environment by using three different substrate sizes. Initial attempts to transfer the multijunction silicon process were made using a 0.1-m{sup 2} substrate (approximately 1 ft{sup 2}). These efforts resulted in a module with a measured aperture area efficiency of 10.32%. Simultaneous with the transfer of the silicon technology, the most complicated aspect of the technology transfer, Solarex began process development techniques on large-area modules by using the 0.37-m{sup 2} substrates. These efforts resulted in modules with a total area efficiency of 7%. Finally, initial runs on substrates 0.74 m{sup 2} were made to debug the large-area equipment in preparation of transferring the knowledge gained in the processing of the smaller substrates.

  16. Tripple Junction Solar Cells With 30.0% Efficiency And Next Generation Cell Concepts

    NASA Astrophysics Data System (ADS)

    Kostler, W.; Meusel, M.; Kubera, T.; Torunski, T.

    2011-10-01

    This paper presents the data of the AZUR SPACE 3G30 cell. With its 30% BOL efficiency for AM0, it marks the final stage of lattice-matched space triple-junction cells. Furthermore, a summary is given on the roadmap for the development of future cell concept in terms of higher efficiency and increase of cell size.

  17. Light management and efficient carrier generation with a highly transparent window layer for a multijunction amorphous silicon solar cell

    NASA Astrophysics Data System (ADS)

    Iftiquar, Sk Md; Lee, Jeong Chul; Lee, Jieun; Kim, Youngkuk; Jang, Juyeon; Lee, Yeun-Jung; Yi, Junsin

    2013-01-01

    P-layer of a p-i-n type amorphous silicon solar cell helps in creating a built-in electric field inside the cell; it also contributes to parasitic absorption loss of incident light. Here, we report optimization of these two characteristic contributions of the p-layer of the cell. We used a highly transparent p-type hydrogenated amorphous silicon carbide (p-a-Si1-xCx:H) window layer in an amorphous silicon solar cell. With the increased transparency of the p-type layer, the solar cell showed an improvement in short-circuit current density by 17%, along with improvement in blue response of its external quantum efficiency, although further thinner p-layer showed lower open-circuit voltage. Such a cell shows low light-induced degradation and a promise to be used in high-efficiency multijunction solar cell.

  18. Stable, high-efficiency amorphous-silicon solar cells with low hydrogen content

    NASA Astrophysics Data System (ADS)

    Hegedus, S. S.; Phillips, J. E.

    1993-08-01

    This report describes a 21-month project to demonstrate amorphous-silicon (a-Si) solar cells with high stabilized conversion efficiency. The objective was to develop a research program spanning material issues (more stable a-Si and better a-SiGe alloys) and device issues (more stable a-Si-based solar cells) with the goal of high stabilized solar cell efficiency. The Institute of Energy Conversion (IEC) produced and analyzed the stability of a-Si films and solar cells with reduced hydrogen content (2-6%). A thermodynamic model of defect formation was developed that describes the high-temperature degraded state of a solar cell. An analysis of bi-facial current voltage and quantum efficiency results for a-SiGe p-i-n devices with transparent front and back contacts provided information about the influence of alloying and band-gap grading on hole and electron collection. IEC also studied the stability of graded and ungraded a-SiGe solar cells using bifacial devices to learn about the relative degradation of hole and electron collection, and concludes that degradation of the photoconductivity of a-SiGe materials does not agree with degradation observed in solar cells.

  19. Research on stable, high-efficiency, large-area, amorphous-silicon-based submodules

    SciTech Connect

    Delahoy, A.E.; Tonon, T.; Macneil, J. )

    1991-06-01

    The primary objective of this subcontract is to develop the technology for same bandgap, amorphous silicon tandem junction photovoltaic modules having an area of at least 900 cm{sup 2} with the goal of achieving an aperture area efficiency of 9%. A further objective is to demonstrate modules that retain 95% of their under standard light soaking conditions. Our approach to the attainment of these objective is based on the following distinctive technologies: (a) in-house deposition of SiO{sub 2}/SnO{sub 2}:F onto soda lime glass by APCVD to provide a textured, transparent electrode, (b) single chamber r.f. flow discharge deposition of the a-Si:H layers onto vertical substrates contained with high package density in a box carrier'' to which the discharge is confined (c) sputter deposition of highly reflecting, ZnO-based back contacts, and (d) laser scribing of the a-Si:H and electrodes with real-time scribe tracking to minimize area loss. Continued development of single junction amorphous silicon was aggressively pursued as proving ground for various optical enhancement schemes, new p-layers, and i-layers quality. We have rigorously demonstrated that the introduction of a transitional i-layer does not impair stability and that the initial gain in performance is retained. We have demonstrated a small improvement in cell stability through a post-fabrication treatment consisting of multiple, intense light flashes followed by sufficient annealing. Finally, several experiments have indicated that long term stability can be improved by overcoating the SnO{sub 2} with ZnO. 25 refs., 17 figs.

  20. Seismicity Associated with a Stranded Plate Fragment Above the Juan de Fuca Slab in the Vicinity of the Mendocino Triple Junction

    NASA Astrophysics Data System (ADS)

    McCrory, P. A.; Waldhauser, F.; Oppenheimer, D. H.; Blair, J. L.

    2011-12-01

    Our new model of the subducted Juan de Fuca (JdF) plate beneath western North America, combined with the spatial resolution of double-differenced earthquake relocations, offers new insights regarding subsurface seismic sources in the complex tectonic setting near the Mendocino triple junction. Relocated seismicity resolves a double seismic zone within the slab beneath northwestern California that strongly constrains the location of the plate interface and delineates a cluster of seismicity ~10 km above the interface that includes the April 1992 M7.1 Cape Mendocino earthquake near its eastern edge. This cluster does not just represent aftershocks to the M7.1 event, but has persisted through time. About half of the earthquakes within the cluster occurred within the year following the April 1992 event. However, the remaining earthquakes either occurred within the 17 years preceding April 1992 or the 17 years following April 1993. The seismogenic structure forms a triangular shape approximately 80-km long in a north-south direction and up to 50-km long in a west-east direction. The structure is up to 8-km thick, and its surface dips gently landward from depths of ~6 to 14 km. Interpretation of the M7.1 event as occurring above the subduction interface requires a more complex slab geometry than previously envisioned. Specifically, the slab just east of the trench dips about 15° and then flattens to a dip of just a few degrees from ~15-25 km before it steepens again to about 25° from ~25-45 km, which is the maximum depth it can be imaged by hypocenters. The seismicity cluster is situated above the slab where it flexes concave upward in the transition from its initial moderate dip to a flat dip. Flat slab segments are observed elsewhere around the Pacific Rim where the subducting plate is relatively buoyant owing to young or thick oceanic crust, consistent with this JdF segment which is ~8-5 Ma where it enters the trench. These data provide compelling evidence that a

  1. Block model at the Hatay Triple junction in N-W Syria and S-E Turkey from GPS data inversion

    NASA Astrophysics Data System (ADS)

    Mahmoud, Yasser; Cakir, Ziyadin; Masson, Frédéric; Meghraoui, Mustapha

    2013-04-01

    The active deformation at the Hatay Triple junction (HTJ) in northwest Syria and southeast Turkey is represented by finite number of rotating elastic spherical blocks limited by faults. GPS derived horizontal velocities are inverted for the fault parameters and block angular velocities. We are using GPS vectors from our dense regional GPS network reinforced by other GPS solutions in the region.We test different tectonic configurations trying to minimize the data misfit of our model using a reduced chi-square statistic:χ_n^2=(∑r^2/s2 )/DOF.Residuals were calculated for different models in order to define the best fit to the known kinematic configuration of the region. A block model with the new Iskenderun and Amanous micro blocks and three major blocks of Arabia, Anatolia, and Sinai is essential to explain the GPS vectors. The estimated relative slip rates on faults are similar to other published estimations with some exceptions.The Karasu Fault shows a sinistral slip rate of 4.0 ± 1.0 mm/yr and a compressional behavior with a revers slip rate of 2.1-2.7 mm/yr, which contradicts with the extensional nature proposed by previous studies. The Dead Sea fault experiences a relative slip rate of ~3.5 ± 0.3 mm/yr along all its segments. We also define a new Euler pole for the relative angular velocity of Anatolia-Arabia Euler pole at (27.61oN, 45.127oE, 0.391± 0.056 o/Myr), and a Sinai-Arabia Euler pole at (31.012oN, 46.464oE, 0.202 ± 0.067 o/Myr).A 15 km of locking depth is estimated for the EAF, 4-5 km deeper than that of the Dead Sea Fault. The East Anatolian Fault is however partially locked down to the depths of 30 km with no significant extension or compression. In general, slip rates and kinematics of faults are consistent with the geological observations in the region.

  2. Evolution of the Rodgers Creek–Maacama right-lateral fault system and associated basins east of the northward-migrating Mendocino Triple Junction, northern California

    USGS Publications Warehouse

    McLaughlin, Robert J.; Sarna-Wojcicki, Andrei M.; Wagner, David L.; Fleck, Robert J.; Langenheim, V.E.; Jachens, Robert C.; Clahan, Kevin; Allen, James R.

    2012-01-01

    The Rodgers Creek–Maacama fault system in the northern California Coast Ranges (United States) takes up substantial right-lateral motion within the wide transform boundary between the Pacific and North American plates, over a slab window that has opened northward beneath the Coast Ranges. The fault system evolved in several right steps and splays preceded and accompanied by extension, volcanism, and strike-slip basin development. Fault and basin geometries have changed with time, in places with younger basins and faults overprinting older structures. Along-strike and successional changes in fault and basin geometry at the southern end of the fault system probably are adjustments to frequent fault zone reorganizations in response to Mendocino Triple Junction migration and northward transit of a major releasing bend in the northern San Andreas fault. The earliest Rodgers Creek fault zone displacement is interpreted to have occurred ca. 7 Ma along extensional basin-forming faults that splayed northwest from a west-northwest proto-Hayward fault zone, opening a transtensional basin west of Santa Rosa. After ca. 5 Ma, the early transtensional basin was compressed and extensional faults were reactivated as thrusts that uplifted the northeast side of the basin. After ca. 2.78 Ma, the Rodgers Creek fault zone again splayed from the earlier extensional and thrust faults to steeper dipping faults with more north-northwest orientations. In conjunction with the changes in orientation and slip mode, the Rodgers Creek fault zone dextral slip rate increased from ∼2–4 mm/yr 7–3 Ma, to 5–8 mm/yr after 3 Ma. The Maacama fault zone is shown from several data sets to have initiated ca. 3.2 Ma and has slipped right-laterally at ∼5–8 mm/yr since its initiation. The initial Maacama fault zone splayed northeastward from the south end of the Rodgers Creek fault zone, accompanied by the opening of several strike-slip basins, some of which were later uplifted and compressed

  3. Efficient nanorod-based amorphous silicon solar cells with advanced light trapping

    SciTech Connect

    Kuang, Y.; Lare, M. C. van; Polman, A.; Veldhuizen, L. W.; Schropp, R. E. I.; Rath, J. K.

    2015-11-14

    We present a simple, low-cost, and scalable approach for the fabrication of efficient nanorod-based solar cells. Templates with arrays of self-assembled ZnO nanorods with tunable morphology are synthesized by chemical bath deposition using a low process temperature at 80 °C. The nanorod templates are conformally coated with hydrogenated amorphous silicon light absorber layers of 100 nm and 200 nm thickness. An initial efficiency of up to 9.0% is achieved for the optimized design. External quantum efficiency measurements on the nanorod cells show a substantial photocurrent enhancement both in the red and the blue parts of the solar spectrum. Key insights in the light trapping mechanisms in these arrays are obtained via a combination of three-dimensional finite-difference time-domain simulations, optical absorption, and external quantum efficiency measurements. Front surface patterns enhance the light incoupling in the blue, while rear side patterns lead to enhanced light trapping in the red. The red response in the nanorod cells is limited by absorption in the patterned Ag back contact. With these findings, we develop and experimentally realize a further advanced design with patterned front and back sides while keeping the Ag reflector flat, showing significantly enhanced scattering from the back reflector with reduced parasitic absorption in the Ag and thus higher photocurrent generation. Many of the findings in this work can serve to provide insights for further optimization of nanostructures for thin-film solar cells in a broad range of materials.

  4. Detective quantum efficiency of an amorphous selenium detector to megavoltage radiation.

    PubMed

    Mah, D; Rawlinson, J A; Rowlands, J A

    1999-05-01

    The spatial frequency dependent detective quantum efficiency (DQE(f)) of a high-resolution selenium-based imaging system has been measured at megavoltage energies. These results have been compared with theoretical calculations. The imaging system was a video tube with a 5 microm amorphous selenium (a-Se) target which was irradiated by 1.25 MeV gamma-rays. The modulation transfer function (MTF) decreased rapidly with spatial frequency (determined by spread of electrons in the build-up material) while the noise power spectrum was constant as a function of spatial frequency. The DQE obtained from these MTF and noise power measurements was compared with a Monte Carlo model of the pulse height spectrum of the detector. The DQE(0) model accounted for the interaction of x rays with the detector as well as the energy-dependent gain (charge generated/energy deposition). Good agreement between the calculated and measured DQE(0) was found. The model was also used to estimate the DQE(f) of a metal plate + a-Se detector which was compared with a metal plate + phosphor system of the same mass thickness. The DQE(f) s of both detectors are very similar, indicating that the choice of which detector is better will be based upon criteria other than DQE(f), such as read-out approach, ease of manufacture or sensitivity. PMID:10368025

  5. Amorphous silicon research. Final technical progress report, 1 August 1994--28 February 1998

    SciTech Connect

    Guha, S

    1998-05-01

    This report describes the status and accomplishments of work performed under this subcontract by United Solar Systems. United Solar researchers explored several new deposition regimes/conditions to investigate their effect on material/device performance. To facilitate optimum ion bombardment during growth, a large parameter space involving chamber pressure, rf power, and hydrogen dilution were investigated. United Solar carried out a series of experiments using discharge modulation at various pulsed-plasma intervals to study the effect of Si-particle incorporation on solar cell performance. Hydrogen dilution during deposition is found to improve both the initial and stable performance of a-Si and a-SiGe alloy cells. Researchers conducted a series of temperature-ramping experiments on samples prepared with high and low hydrogen dilutions to study the effect of hydrogen effusion on solar cell performance. Using an internal photoemission method, the electrical bandgap of a microcrystalline p layer used in high-efficiency solar cells was measured to be 1.6 eV. New measurement techniques were developed to evaluate the interface and bulk contributions of losses to solar cell performance. Researchers replaced hydrogen with deuterium and found deuterated amorphous silicon alloy solar cells exhibit reduced light-induced degradation. The incorporation of a microcrystalline n layer in a multijunction cell is seen to improve cell performance. United Solar achieved a world-record single-junction a-Si alloy stable cell efficiency of 9.2% with an active area of 0.25 cm{sup 2} grown with high hydrogen dilution. They also achieved a world-record triple-junction, stable, active-area cell efficiency of 13.0% with an active area of 0.25 cm{sup 2}.

  6. Highly efficient water splitting by a dual-absorber tandem cell

    NASA Astrophysics Data System (ADS)

    Brillet, Jeremie; Yum, Jun-Ho; Cornuz, Maurin; Hisatomi, Takashi; Solarska, Renata; Augustynski, Jan; Graetzel, Michael; Sivula, Kevin

    2012-12-01

    Photoelectrochemical water-splitting devices, which use solar energy to convert water into hydrogen and oxygen, have been investigated for decades. Multijunction designs are most efficient, as they can absorb enough solar energy and provide sufficient free energy for water cleavage. However, a balance exists between device complexity, cost and efficiency. Water splitters fabricated using triple-junction amorphous silicon or III-V semiconductors have demonstrated reasonable efficiencies, but at high cost and high device complexity. Simpler approaches using oxide-based semiconductors in a dual-absorber tandem approach have reported solar-to-hydrogen (STH) conversion efficiencies only up to 0.3% (ref. 4). Here, we present a device based on an oxide photoanode and a dye-sensitized solar cell, which performs unassisted water splitting with an efficiency of up to 3.1% STH. The design relies on carefully selected redox mediators for the dye-sensitized solar cell and surface passivation techniques and catalysts for the oxide-based photoanodes.

  7. From Kings Peak to the Delgado submarine canyon: Tracking littoral inputs to the deep sea at the Mendocino Triple Junction, California

    NASA Astrophysics Data System (ADS)

    Davidson, C. J.; Di Fiori, R. V.; Smith, M. E.; Mueller, E. R.

    2011-12-01

    Gravel coarse enough to overcome viscous damping and impact bedrock underwater is thought prerequisite for incision of submarine canyons, yet with few exceptions, canyons off the California coast have headwalls >2 km offshore at the shelf edge and below storm wave base. This suggests effective disconnection from modern coarse littoral sediment fluxes, and implies they are relict Pleistocene features only actively incised during glacial periods. North of the Transverse Ranges only five submarine canyons approach shore closer than 500 m, and are coincident areas of rapid uplift. Although canyons occur adjacent to major upland-draining streams that transport coarse sediment, submarine canyon headwalls are often laterally offset from stream mouths by ~1-2 km. Coarse stream sediment thus requires littoral transport to enter canyon heads and induce incision. To better understand the evolution of coarse sediment through the littoral system, we measured the texture and composition of coarse sediment in streams and beaches directly onshore of the Delgado submarine canyon, which lies offshore of the fastest uplifting segment of the King Range and onshore the Mendocino Triple Junction. Adjacent to the Delgado Canyon inlet, coarse (d50 > 360 mm) sediment enters the littoral zone from three streams, and is transported alongshore in a predominantly southeast direction. Stream-derived alluvium is comprised of a poorly to moderately sorted mixture of angular to subrounded clasts of well-cemented sandstone (d50 = 256-725 mm) and fissile siliciclastic mudstone (d50 = 90-256 mm). Well sorted and rounded beach gravels adjacent to stream mouths are similarly coarse, and clasts larger than 1 m diameter extend 200-400 meters eastward from stream mouths. In contrast, sediment entering the littoral zone from hillslope erosion between streams is finer (d50 ~16 mm) and is exclusively comprised of pervasively-folded siliciclastic mudstone. Immediately adjacent the Delgado canyon headwall

  8. Signal, noise, and detective quantum efficiency of amorphous-silicon:hydrogen flat-panel imagers

    NASA Astrophysics Data System (ADS)

    Siewerdsen, Jeffrey Harold

    Flat-panel imagers based upon the technology of thin-film amorphous silicon transistors and photodiodes are under investigation for a wide variety of medical imaging applications. This thesis presents quantitative empirical and theoretical investigations of the imaging performance of such imaging systems. Performance was evaluated in terms of imager signal size, spatial resolution, noise characteristics, and signal-to-noise ratio for a wide variety of imaging system configurations and exposure conditions relevant to medical imaging. A theoretical model based upon cascaded systems analysis allowed prediction of imager signal, noise, and detective quantum efficiency (DQE), and theoretical results were found to agree well with empirical measurements. The empirical and theoretical analyses yielded quantification of the performance of existing imager designs, allowed investigation of the potential performance of future flat-panel imaging systems, and provided a methodology for identifying optimal imager configurations for various applications and imaging tasks. There is every indication that flat-panel imagers could provide performance superior to that of existing clinical imaging technologies. For example, in general x-ray radiography, mammography, and radiotherapy portal imaging, such systems could provide DQE exceeding 60%, 80%, and 1.5%, respectively, approximately twice that of film-based systems. However, for applications involving very low exposures per image, e.g., real-time fluoroscopy, such systems may suffer from reduced signal-to-noise ratio. The analyses developed in this thesis provide an effective means of identifying strategies for improved imager performance and will facilitate the realization of optimized flat-panel imagers that physically achieve their maximum theoretical performance.

  9. Stable, high-efficiency amorphous silicon solar cells with low hydrogen content

    SciTech Connect

    Fortmann, C.M.; Hegedus, S.S. )

    1992-12-01

    Results and conclusions obtained during a research program of the investigation of amorphous silicon and amorphous silicon based alloy materials and solar cells fabricated by photo-chemical vapor and glow discharge depositions are reported. Investigation of the effects of the hydrogen content in a-si:H i-layers in amorphous silicon solar cells show that cells with lowered hydrogen content i-layers are more stable. A classical thermodynamic formulation of the Staebler-Wronski effect has been developed for standard solar cell operating temperatures and illuminations. Methods have been developed to extract a lumped equivalent circuit from the current voltage characteristic of a single junction solar cell in order to predict its behavior in a multijunction device.

  10. Stable, high-efficiency amorphous silicon solar cells with low hydrogen content

    NASA Astrophysics Data System (ADS)

    Fortmann, C. M.; Hegedus, S. S.

    1992-12-01

    Results and conclusions obtained during the investigation of amorphous silicon, amorphous silicon based alloy materials, and solar cells fabricated by photo-chemical vapor and glow discharge depositions are reported. Investigation of the effects of the hydrogen content in a-Si:H i-layers in amorphous silicon solar cells show that cells with lowered hydrogen content i-layers are more stable. A classical thermodynamic formulation of the Staebler-Wronski effect has been developed for standard solar cell operating temperatures and illuminations. Methods have been developed to extract a lumped equivalent circuit from the current voltage characteristic of a single junction solar cell in order to predict its behavior in a multijunction device.

  11. Performance and modeling of amorphous silicon photovoltaics for building-integrated applications

    SciTech Connect

    Kroposki, B.; Hansen, R.

    1999-07-01

    Amorphous silicon photovoltaic (PV) modules offer several advantages for building-integrated applications. The material can be deposited on glass or flexible substrates, which allows for products like roofing shingles and integrated PV/building glass. The material also has a uniform surface, which is ideal for many architectural applications. Amorphous silicon modules perform well in warm weather and have a small temperature coefficient for power. Depending on the building load, this may be beneficial when compared to crystalline systems. At the National Renewable Energy Laboratory, the authors are monitoring the performance of a triple-junction a-Si system. The system consists of 72 roofing shingles mounted directly to simulated roofing structures. This paper examines the performance of the building-integrated amorphous silicon PV system and applicability for covering residential loads. A simple model of system performance is also developed and is presented.

  12. Ketjenblack carbon supported amorphous manganese oxides nanowires as highly efficient electrocatalyst for oxygen reduction reaction in alkaline solutions.

    PubMed

    Lee, Jang-Soo; Park, Gi Su; Lee, Ho Il; Kim, Sun Tai; Cao, Ruiguo; Liu, Meilin; Cho, Jaephil

    2011-12-14

    A composite air electrode consisting of Ketjenblack carbon (KB) supported amorphous manganese oxide (MnOx) nanowires, synthesized via a polyol method, is highly efficient for the oxygen reduction reaction (ORR) in a Zn-air battery. The low-cost and highly conductive KB in this composite electrode overcomes the limitations due to low electrical conductivity of MnOx while acting as a supporting matrix for the catalyst. The large surface area of the amorphous MnOx nanowires, together with other microscopic features (e.g., high density of surface defects), potentially offers more active sites for oxygen adsorption, thus significantly enhancing ORR activity. In particular, a Zn-air battery based on this composite air electrode exhibits a peak power density of ∼190 mW/cm2, which is far superior to those based on a commercial air cathode with Mn3O4 catalysts. PMID:22050041

  13. Glacial-interglacial trench supply variation, spreading-ridge subduction, and feedback controls on the Andean margin development at the Chile triple junction area (45-48°S)

    NASA Astrophysics Data System (ADS)

    Bourgois, Jacques; Guivel, Christele; Lagabrielle, Yves; Calmus, Thierry; BoulèGue, Jacques; Daux, ValéRie

    2000-04-01

    During the Chile triple junction (CTJ) cruise (March-April 1997), EM12 bathymetry and seismic reflection data were collected in the vicinity of the Chile triple junction (45-480S), where an active spreading ridge is being subducted beneath the Andean continental margin. Results show a continental margin development shaped by tectonic processes spanning a spectrum from subduction-erosion to subduction-accretion. The Andean continental margin and the Chile trench exhibit a strong segmentation which reflects the slab segmentation and the Chile triple junction migration. Three segments were identified along the Andean continental margin: the presubduction, the synsubduction, and the postsubduction segments, from north to south. Both climate-induced variations of the sediment supply to the trench and the tectonic reorganization at the Nazca-Antarctica plate boundary involving postsubduction ridge jump are the two main factors that control the tectonic regime of this continental margin. Along the survey area we infer the succession of two different periods during the last glacial-interglacial cycle: a glacial period with ice-rafted detrital discharges restricted to the shoreline area and low river output and a warmer period during which the Andean ice cap retreat allowed the Andes to be drained off. During these warm periods, rapid increase in trench deposition caused the margin to switch from subductionerosion or nonaccretion to subduction-accretion: (1) along the presubduction segment after the last deglaciation and (2) along the postsubduction segment after the interglacial episode at 130-117 ka. Conversely, a nonaccretion or subduction-érosion mode characterized the presubduction and postsubduction segments during glacial maximums. The major effects of subduction of the buoyant Chile ridge include a shallow trench which diverts trench sediment supply and tectonic instabilities at the Nazca-Antarctica plate boundary. We suggest that a postsubduction westward jump of

  14. Research on stable, high-efficiency amorphous silicon multijunction modules. Annual subcontract report, 1 January 1992--28 February 1993

    SciTech Connect

    Guha, S.

    1993-07-01

    This report describes the progress made during Phase 2 of the R&D program to obtain high-efficiency amorphous alloy multijunction PV (photovoltaic) modules. The highlight of the work includes: (1) demonstration of world-record small-area efficiency of 11.2% after one-sun light-soaking at 50{degrees}C for 600 h using a dual band gap, double-junction structure; and (2) demonstration of initial module efficiency of 10.6% over 0.09-m{sup 2} (1-ft{sup 2}) area using the same double-junction approach. In addition, fundamental studies on material properties and cell performance have shown an interesting correlation between microstructure in the material and cell efficiency both in the initial and light-degraded conditions.

  15. Research on high-efficiency, single-junction, monolithic, thin-film amorphous silicon solar cells: Annual subcontract report, May 1985 - Jul 1986

    SciTech Connect

    Wiesmann, H.; Dolan, J.; Fricano, G.; Danginis, V.

    1987-02-01

    A study was undertaken of the optoelectronic properties of amorphous silicon-hydrogen thin films deposited from disilane at high deposition rates. The information derived from this study was used to fabricate amorphous silicon solar cells with efficiencies exceeding 7%. The intrinsic layer of these solar cells was deposited at 15 angstroms/second. Material properties investigated included dark conductivity, photoconductivity, minority carrier diffusion length, and density of states. The solar cells properties characterized were absolute quantum yield and simulated global AM 1.5 efficiencies. Investigations were undertaken utilizing optical and infrared spectroscopy to optimize the microstructures of the intrinsic amorphous silicon. That work was sponsored by the New York State Energy Research and Development Authority. The information was used to optimize the intrinsic layer of amorphous silicon solar cells, resulting in AM 1.5 efficiencies exceeding 7%.

  16. Light-induced V{sub oc} increase and decrease in high-efficiency amorphous silicon solar cells

    SciTech Connect

    Stuckelberger, M. Riesen, Y.; Despeisse, M.; Schüttauf, J.-W.; Haug, F.-J.; Ballif, C.

    2014-09-07

    High-efficiency amorphous silicon (a-Si:H) solar cells were deposited with different thicknesses of the p-type amorphous silicon carbide layer on substrates of varying roughness. We observed a light-induced open-circuit voltage (V{sub oc}) increase upon light soaking for thin p-layers, but a decrease for thick p-layers. Further, the V{sub oc} increase is enhanced with increasing substrate roughness. After correction of the p-layer thickness for the increased surface area of rough substrates, we can exclude varying the effective p-layer thickness as the cause of the substrate roughness dependence. Instead, we explain the observations by an increase of the dangling-bond density in both the p-layer—causing a V{sub oc} increase—and in the intrinsic absorber layer, causing a V{sub oc} decrease. We present a mechanism for the light-induced increase and decrease, justified by the investigation of light-induced changes of the p-layer and supported by Advanced Semiconductor Analysis simulation. We conclude that a shift of the electron quasi-Fermi level towards the conduction band is the reason for the observed V{sub oc} enhancements, and poor amorphous silicon quality on rough substrates enhances this effect.

  17. Higher than 60% internal quantum efficiency of photoluminescence from amorphous silicon oxynitride thin films at wavelength of 470 nm

    SciTech Connect

    Zhang, Pengzhan; Chen, Kunji Zhang, Pei; Fang, Zhonghui; Li, Wei; Xu, Jun; Huang, Xinfan; Dong, Hengping

    2014-07-07

    We reported the study on the photoluminescence internal quantum efficiency (PL IQE) and external quantum efficiency (PL EQE) from the amorphous silicon oxynitride (a-SiNO) films, which were fabricated by plasma-enhanced chemical vapor deposition followed by in situ plasma oxidation. We employed the direct measurement of absolute quantum efficiency within a calibrated integration sphere to obtain the PL EQE. Then, we calculated the PL IQE by combing the measured EQE and optical parameters of light extraction factor, reflectivity, and transmittance of the a-SiNO thin films. We also derived the PL QE through investigating the characteristic of the temperature dependent PL. These results show that the PL IQE as high as 60% has been achieved at peak wavelength of about 470 nm, which is much higher than that of Si nanocrystal embedded thin films.

  18. Research on stable, high-efficiency amorphous silicon multijunction modules. Semiannual subcontract report, 1 March 1993--30 November 1993

    SciTech Connect

    Guha, S.

    1994-03-01

    This report describes the progress made during the first half of Phase III of the R&D program to obtain high-efficiency amorphous silicon alloy multijunction modules. The highlight of the work includes (1) demonstration of the world`s highest initial module efficiency (area of 0.09 m{sup 2}) of 11.4% as confirmed by NREL, and (2) demonstration of stable module efficiency of 9.5% after 1-sun light soaking for 1000 h at 50{degrees}C. In addition, fundamental studies were carried out to improve material properties of the component cells of the multijunction structure and to understand the optical losses associated with the back reflector.

  19. Research on high-efficiency, single-junction, monolithic, thin-film amorphous silicon solar cells. Semiannual subcontract progress report, 1 December 1984-31 May 1985

    SciTech Connect

    Ashton, G.R.; Aspen, F.E.; Jacobson, R.L.; Jeffrey, F.R.; Tran, N.T.

    1986-01-01

    This report presents interim results of research in high-efficiency, single-junction, monolithic thin-film amorphous silicon solar cells, which consists of five research tasks: (1) amorphous silicon materials research, (2) nonsemiconductor materials research, (3) solar cell research, (4) monolithic, intraconnected cells/submodule research, and (5) multichamber deposition system research. The subcontracted work reported here advances the state of the art in thin-film amorphous silicon solar cell development through work on flexible substrates. A multichamber deposition system for depositing a-Si onto polyimide flexible web is essentially complete.

  20. Research on stable, high-efficiency amorphous silicon multijunction modules. Annual subcontract report, 1 November 1992--31 May 1993

    SciTech Connect

    Ghosh, M.; Kampas, F.; Xi, J.

    1993-09-01

    This report describes progress made in the first half of Phase II of a three-phase program to develop high-efficiency, same-band-gap, amorphous-silicon, tandem-junction modules. Results for both 1-cm- {sup 2} devices and 0.3-m (0.09-m{sup 2}) modules are given. considerable effort was devoted to finding a device structure and layer conditions that reconcile the conflicting requirements of a good ``tunnel junction`` contact between the two stacks and a high-efficiency device. High-band-gap p{sub 2}layers, which enable good voltage and current from the second stack, were found to result in poor tunnel junctions. The best results were obtained by using a thin (1-nm-thick) p{sup +} layer (no carbon) between the n{sub 1} and p{sub 2} layers of the device.

  1. Performance and Modeling of Amorphous Silicon Photovoltaics for Building-Integrated Applications (Preprint prepared for Solar 99)

    SciTech Connect

    Kroposki, B.; Hansen, R.

    1998-06-07

    Amorphous silicon photovoltaic (PV) modules offer several advantages for building-integrated applications. The material can be deposited on glass or flexible substrates, which allows for products like roofing shingles and integrated PV/building glass. The material also has a uniform surface, which is ideal for many architectural applications. Amorphous silicon modules perform well in warm weather and have a small temperature coefficient for power. Depending on the building load, this may be beneficial when compared to crystalline systems. At the National Renewable Energy Laboratory, we are monitoring the performance of a triple-junction a-Si system. The system consists of 72 roofing shingles mounted directly to simulated roofing structures. This paper examines the performance of the building-integrated amorphous silicon PV system and applicability for covering residential loads. A simple model of system performance is also developed and is presented.

  2. Research on stable, high-efficiency amorphous silicon multijunction modules. Semiannual subcontract report, 1 January 1990--30 June 1991

    SciTech Connect

    Guha, S.

    1991-12-01

    This report describes research to improve the understanding of amorphous silicon alloys and other relevant non-semiconductor materials for use in high-efficiency, large-area multijunction modules. The research produced an average subcell initial efficiency of 8.8% over a 1-ft{sup 2} area using same-band-gap, dual-junction cells deposited over a ZnO/AlSi back reflector. An initial efficiency of 9.6% was achieved using a ZnO/Ag back reflector over smaller substrates. A sputtering machine will be built to deposit a ZnO/Ag back reflector over a 1-ft{sup 2} area so that a higher efficiency can also be obtained on larger substrates. Calculations have been performed to optimize the grid pattern, bus bars, and cell interconnects on modules. With our present state of technology, we expect a difference of about 6% between the aperture-area and active-area efficiencies of modules. Preliminary experiments show a difference of about 8%. We can now predict the performance of single-junction cells after long-term light exposure at 50{degree}C by exposing cells to short-term intense light at different temperatures. We find that single-junction cells deposited on a ZnO/Ag back reflector show the highest stabilized efficiency when the thickness of the intrinsic layers is about 2000 {angstrom}. 8 refs.

  3. Dual-Layer Nanostructured Flexible Thin-Film Amorphous Silicon Solar Cells with Enhanced Light Harvesting and Photoelectric Conversion Efficiency.

    PubMed

    Lin, Yinyue; Xu, Zhen; Yu, Dongliang; Lu, Linfeng; Yin, Min; Tavakoli, Mohammad Mahdi; Chen, Xiaoyuan; Hao, Yuying; Fan, Zhiyong; Cui, Yanxia; Li, Dongdong

    2016-05-01

    Three-dimensional (3-D) structures have triggered tremendous interest for thin-film solar cells since they can dramatically reduce the material usage and incident light reflection. However, the high aspect ratio feature of some 3-D structures leads to deterioration of internal electric field and carrier collection capability, which reduces device power conversion efficiency (PCE). Here, we report high performance flexible thin-film amorphous silicon solar cells with a unique and effective light trapping scheme. In this device structure, a polymer nanopillar membrane is attached on top of a device, which benefits broadband and omnidirectional performances, and a 3-D nanostructure with shallow dent arrays underneath serves as a back reflector on flexible titanium (Ti) foil resulting in an increased optical path length by exciting hybrid optical modes. The efficient light management results in 42.7% and 41.7% remarkable improvements of short-circuit current density and overall efficiency, respectively. Meanwhile, an excellent flexibility has been achieved as PCE remains 97.6% of the initial efficiency even after 10 000 bending cycles. This unique device structure can also be duplicated for other flexible photovoltaic devices based on different active materials such as CdTe, Cu(In,Ga)Se2 (CIGS), organohalide lead perovskites, and so forth. PMID:27052357

  4. Analysis on the effect of amorphous photonic crystals on light extraction efficiency enhancement for GaN-based thin-film-flip-chip light-emitting diodes

    NASA Astrophysics Data System (ADS)

    Yue, Qingyang; Li, Kang; Kong, Fanmin; Zhao, Jia; Liu, Meng

    2016-05-01

    This work showed the liquid-like amorphous photonic crystals (PhCs) can effectively enhance the light extraction efficiency of GaN-based thin-film-flip-chip light-emitting diodes (TFFC LEDs) by the light scattering effect. The finite-difference time-domain (FDTD) method was employed to analyze the light scattering characteristics, numerical studies revealed that the amorphous PhCs can provide omnidirectional scattering, and the transmittances of amorphous PhCs is superior to that of triangular lattice PhCs when the incident angle is in the region 20 ° ≤ θ ≤ 35 ° . The influence of p-GaN layer thickness and the amorphous PhCs feature size on the light extraction efficiency was also studied by 3D-FDTD method systematically. For the proposed amorphous PhCs structure in n-GaN layer, the light extraction efficiency is enhanced by a factor of 1.49 as compared to conventional TFFC LEDs, which shows 1.07 times enhancement in comparison to that of triangular lattice PhCs.

  5. Research on stable, high-efficiency, large-area amorphous silicon based modules -- Task B

    SciTech Connect

    Mitchell, K.W.; Willet, D.R. )

    1990-10-01

    This report documents progress in developing a stable, high- efficiency, four-terminal hybrid tandem module. The module consists of a semi-transparent, thin-film silicon:hydrogen alloy (TFS) top circuit and a copper indium diselenide (CuInSe{sub 2}) bottom circuit. Film deposition and patterning processes were successfully extended to 0.4-m{sup 2} substrates. A 33.2-W (8.4% efficient) module with a 3970-cm{sup 2} aperture area and a white back reflector was demonstrated; without the back reflector, the module produced 30.2 W (7.6% efficient). Placing a laminated, 31.6-W, 8.1%-efficient CuInSe{sub 2} module underneath this TFS module, with an air gap between the two, produces 11.2 W (2.9% efficient) over a 3883-cm{sup 2} aperture area. Therefore, the four-terminal tandem power output is 41.4 W, translating to a 10.5% aperture-area efficiency. Subsequently, a 37.8-W (9.7% aperture-area efficiency) CuInSe{sub 2} module was demonstrated with a 3905-cm{sup 2} aperture area. Future performances of single-junction and tandem modules of this size were modeled, and predicted power outputs exceed 50 W (13% efficient) for CuInSe{sub 2} and 65 W (17% efficient) for TFS/CuInSe{sub 2} tandem modules.

  6. Surprising increase in photostability of organic amorphous materials by efficient molecular packing

    NASA Astrophysics Data System (ADS)

    Qiu, Yue; Antony, Lucas; de Pablo, Juan; Ediger, Mark

    Photochemically robust materials are desired for organic electronics. Previous work has demonstrated that crystal packing can strongly influence photochemical reactivity. In amorphous materials, however, similar efforts to tune photostability have not been successful. In this work, we show that organic glasses prepared by physical vapor deposition can be highly stable against photo-isomerization. Disperse orange 37 (DO37), an azobenzene derivative, is studied as a model molecule. The thickness and molecular orientation of DO37 thin films can be altered by the photo-isomerization reaction. We use spectroscopic ellipsometry to measure sample thickness and molecular orientation during light irradiation. By changing the substrate temperature during the deposition, photostability can increase 2 to 3 orders of magnitude relative to the liquid-cooled glass. We find that photostability correlates with density of packing, with density increases of up to 1.3%. Simulations also show that glasses with higher density can be significantly more photo-stable. These results show for the first time that photostability of glasses can be significantly modulated by molecular packing. And they may provide insight in designing organic photovoltaics and light emission devices with longer lifetimes.

  7. Amorphous cobalt potassium phosphate microclusters as efficient photoelectrochemical water oxidation catalyst

    NASA Astrophysics Data System (ADS)

    Zhang, Ye; Zhao, Chunsong; Dai, Xuezeng; Lin, Hong; Cui, Bai; Li, Jianbao

    2013-12-01

    A novel amorphous cobalt potassium phosphate hydrate compound (KCoPO4·H2O) is identified to be active photocatalyst for oxygen evolution reaction (OER) to facilitate hydrogen generation from water photolysis. It has been synthesized through a facile and cost-effective solution-based precipitation method using earth-abundant materials. Its highly porous structure and large surface areas are found to be responsible for the excellent electrochemical performance featuring a low OER onset at ˜550 mVSCE and high current density in alkaline condition. Unlike traditional cobalt-based spinel oxides (Co3O4, NiCo2O4) and phosphate (Co-Pi, Co(PO3)2) electrocatalysts, with proper energy band alignment for light-assisted water oxidation, cobalt potassium phosphate hydrate also exhibits robust visible-light response, generating a photocurrent density of ˜200 μA cm-2 at 0.7 VSCE. This catalyst could thus be considered as a promising candidate to perform photoelectrochemical water splitting.

  8. Homo-Tandem Polymer Solar Cells with VOC >1.8 V for Efficient PV-Driven Water Splitting.

    PubMed

    Gao, Yangqin; Le Corre, Vincent M; Gaïtis, Alexandre; Neophytou, Marios; Hamid, Mahmoud Abdul; Takanabe, Kazuhiro; Beaujuge, Pierre M

    2016-05-01

    Efficient homo-tandem and triple-junction polymer solar cells are constructed by stacking identical subcells composed of the wide-bandgap polymer PBDTTPD, achieving power conversion efficiencies >8% paralleled by open-circuit voltages >1.8 V. The high-voltage homo-tandem is used to demonstrate PV-driven electrochemical water splitting with an estimated solar-to-hydrogen conversion efficiency of ≈6%. PMID:26946165

  9. Impact of the hydrogen content on the photoluminescence efficiency of amorphous silicon alloys

    SciTech Connect

    Kistner, J.; Schubert, M. B.

    2013-12-07

    This paper analyzes the impact of hydrogen on the photoluminescence (PL) efficiency of the three wide gap silicon alloys: silicon carbide (a-SiC{sub x}), silicon nitride (a-SiN{sub x}): silicon oxide (a-SiO{sub x}). All three materials behave similarly. The progression of the PL efficiency over the Si content splits into two regions. With decreasing Si content, the PL efficiency increases until a maximum is reached. With a further decrease of the Si content, the PL efficiency declines again. A comprehensive analysis of the sample structure reveals that the PL efficiency depends on the degree of passivation of Si and Y atoms (Y = C, N, O) with hydrogen. For samples with a high Si content, an effective passivation of incorporated Y atoms gives rise to an increasing PL efficiency. The PL efficiency of samples with a low Si content is limited due to a rising amount of unpassivated Si defect states. We find that a minimum amount of 0.2 H atoms per Si atom is required to maintain effective luminescence.

  10. Amorphous Ni-B alloy nanoparticle film on Ni foam: rapid alternately dipping deposition for efficient overall water splitting

    NASA Astrophysics Data System (ADS)

    Liang, Yanhui; Sun, Xuping; Asiri, Abdullah M.; He, Yuquan

    2016-03-01

    It is highly attractive, but still remains challenging, to develop noble metal-free bifunctional electrocatalysts efficient for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline media. In this letter, we describe the rapid electroless deposition of amorphous Ni-B nanoparticle film on Ni foam (Ni-B/Ni foam) by alternative dipping of Ni foam into Ni precursor and reducing solutions. This Ni-B/Ni foam acts as an efficient and durable 3D catalytic electrode for water splitting, affording 100 mA cm-2 at 360 mV overpotential for the OER and 20 mA cm-2 at 125 mV overpotential for the HER in 1.0 M KOH, and its two-electrode electrolyzer demands a cell voltage of 1.69 V to afford 15 mA cm-2 water-splitting current. Moreover, the catalyst loading can be easily tuned and this alternately dipping deposition technique works universally for other conductive substrates.

  11. Amorphous Ni-B alloy nanoparticle film on Ni foam: rapid alternately dipping deposition for efficient overall water splitting.

    PubMed

    Liang, Yanhui; Sun, Xuping; Asiri, Abdullah M; He, Yuquan

    2016-03-29

    It is highly attractive, but still remains challenging, to develop noble metal-free bifunctional electrocatalysts efficient for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline media. In this letter, we describe the rapid electroless deposition of amorphous Ni-B nanoparticle film on Ni foam (Ni-B/Ni foam) by alternative dipping of Ni foam into Ni precursor and reducing solutions. This Ni-B/Ni foam acts as an efficient and durable 3D catalytic electrode for water splitting, affording 100 mA cm(-2) at 360 mV overpotential for the OER and 20 mA cm(-2) at 125 mV overpotential for the HER in 1.0 M KOH, and its two-electrode electrolyzer demands a cell voltage of 1.69 V to afford 15 mA cm(-2) water-splitting current. Moreover, the catalyst loading can be easily tuned and this alternately dipping deposition technique works universally for other conductive substrates. PMID:26891459

  12. Thermodynamic and achievable efficiencies for solar-driven electrochemical reduction of carbon dioxide to transportation fuels

    PubMed Central

    Singh, Meenesh R.; Clark, Ezra L.; Bell, Alexis T.

    2015-01-01

    Thermodynamic, achievable, and realistic efficiency limits of solar-driven electrochemical conversion of water and carbon dioxide to fuels are investigated as functions of light-absorber composition and configuration, and catalyst composition. The maximum thermodynamic efficiency at 1-sun illumination for adiabatic electrochemical synthesis of various solar fuels is in the range of 32–42%. Single-, double-, and triple-junction light absorbers are found to be optimal for electrochemical load ranges of 0–0.9 V, 0.9–1.95 V, and 1.95–3.5 V, respectively. Achievable solar-to-fuel (STF) efficiencies are determined using ideal double- and triple-junction light absorbers and the electrochemical load curves for CO2 reduction on silver and copper cathodes, and water oxidation kinetics over iridium oxide. The maximum achievable STF efficiencies for synthesis gas (H2 and CO) and Hythane (H2 and CH4) are 18.4% and 20.3%, respectively. Whereas the realistic STF efficiency of photoelectrochemical cells (PECs) can be as low as 0.8%, tandem PECs and photovoltaic (PV)-electrolyzers can operate at 7.2% under identical operating conditions. We show that the composition and energy content of solar fuels can also be adjusted by tuning the band-gaps of triple-junction light absorbers and/or the ratio of catalyst-to-PV area, and that the synthesis of liquid products and C2H4 have high profitability indices. PMID:26504215

  13. Thermodynamic and achievable efficiencies for solar-driven electrochemical reduction of carbon dioxide to transportation fuels

    NASA Astrophysics Data System (ADS)

    Singh, Meenesh R.; Clark, Ezra L.; Bell, Alexis T.

    2015-11-01

    Thermodynamic, achievable, and realistic efficiency limits of solar-driven electrochemical conversion of water and carbon dioxide to fuels are investigated as functions of light-absorber composition and configuration, and catalyst composition. The maximum thermodynamic efficiency at 1-sun illumination for adiabatic electrochemical synthesis of various solar fuels is in the range of 32-42%. Single-, double-, and triple-junction light absorbers are found to be optimal for electrochemical load ranges of 0-0.9 V, 0.9-1.95 V, and 1.95-3.5 V, respectively. Achievable solar-to-fuel (STF) efficiencies are determined using ideal double- and triple-junction light absorbers and the electrochemical load curves for CO2 reduction on silver and copper cathodes, and water oxidation kinetics over iridium oxide. The maximum achievable STF efficiencies for synthesis gas (H2 and CO) and Hythane (H2 and CH4) are 18.4% and 20.3%, respectively. Whereas the realistic STF efficiency of photoelectrochemical cells (PECs) can be as low as 0.8%, tandem PECs and photovoltaic (PV)-electrolyzers can operate at 7.2% under identical operating conditions. We show that the composition and energy content of solar fuels can also be adjusted by tuning the band-gaps of triple-junction light absorbers and/or the ratio of catalyst-to-PV area, and that the synthesis of liquid products and C2H4 have high profitability indices.

  14. Thermodynamic and achievable efficiencies for solar-driven electrochemical reduction of carbon dioxide to transportation fuels.

    PubMed

    Singh, Meenesh R; Clark, Ezra L; Bell, Alexis T

    2015-11-10

    Thermodynamic, achievable, and realistic efficiency limits of solar-driven electrochemical conversion of water and carbon dioxide to fuels are investigated as functions of light-absorber composition and configuration, and catalyst composition. The maximum thermodynamic efficiency at 1-sun illumination for adiabatic electrochemical synthesis of various solar fuels is in the range of 32-42%. Single-, double-, and triple-junction light absorbers are found to be optimal for electrochemical load ranges of 0-0.9 V, 0.9-1.95 V, and 1.95-3.5 V, respectively. Achievable solar-to-fuel (STF) efficiencies are determined using ideal double- and triple-junction light absorbers and the electrochemical load curves for CO2 reduction on silver and copper cathodes, and water oxidation kinetics over iridium oxide. The maximum achievable STF efficiencies for synthesis gas (H2 and CO) and Hythane (H2 and CH4) are 18.4% and 20.3%, respectively. Whereas the realistic STF efficiency of photoelectrochemical cells (PECs) can be as low as 0.8%, tandem PECs and photovoltaic (PV)-electrolyzers can operate at 7.2% under identical operating conditions. We show that the composition and energy content of solar fuels can also be adjusted by tuning the band-gaps of triple-junction light absorbers and/or the ratio of catalyst-to-PV area, and that the synthesis of liquid products and C2H4 have high profitability indices. PMID:26504215

  15. Enhancing the efficiency of wastewater treatment by addition of Fe-based amorphous alloy powders with H2O2 in ferrofluid

    NASA Astrophysics Data System (ADS)

    Yang, Chun-Cheng; Bian, Xiu-Fang; Yang, Jian-Fei

    2014-03-01

    Using combination of ferrofluid (FF) and Fe-based amorphous alloy in the advanced treatment of high concentration, organic wastewater was investigated. The addition of Fe73.5Nb3Cu1Si13.5B9 amorphous alloy powders into a FF give rise to a dramatic enhancement in decreasing chemical oxygen demand (COD) and decolorization. The removal rate of COD by using FF that combined Fe73.5Nb3Cu1Si13.5B9 metallic glass (MG) particles reached 92% in the presence of H2O2, nearly more than 50% higher than that by using only FF. Furthermore, compared with the FF, the decolorizing effect of the combination was 20% higher. It has been found that MG powders with the amorphous structures have high efficiency of waste water treatment and lead to high catalytic ability.

  16. Analysis of Triggering of Earthquakes and Tremor in the Western U.S. due to the 2010 El Mayor Cucapah Earthquake and the Mw6.8 Mendocino Triple Junction Earthquake in 2014

    NASA Astrophysics Data System (ADS)

    Hatch, R. L.; Polet, J.

    2014-12-01

    Recent studies indicate that the passage of seismic waves from large earthquakes are able to trigger small earthquakes and tremor at regional distances. These small events may be detected by applying a high-pass filter to seismograms to remove the much larger ground motion amplitudes from the large distant earthquake. Our interests are in examining the local triggering of earthquakes and tremor throughout the West Coast of North America from the magnitude 7.2 El Mayor-Cucapah 2010 earthquake and the magnitude 6.8 Northern California, March 10, 2014 earthquake, just north of the Mendocino Triple Junction. We will present the results of the analysis of waveform data from hundreds of seismometers throughout Southern California, Northern California, Oregon, Washington, as well as some stations bordering these states. Our preliminary results suggest that triggering of local earthquakes and tremor occurred for both earthquakes. In the case of the records of the Southern California stations for the El Mayor Cucapah 2010 earthquake, 27 stations showed triggering near the seismic station. 13 of these stations are located in or near known geothermal areas, while others were located along active faults and one offshore. While conducting this study, we detected an instrumental noise signal present in 63 of the Southern California seismograms for the El Mayor-Cucapah earthquake. Initially, the signal looked like a typical triggered event, yet with further investigation we found its likely cause to be instrumental noise. We plan to relate our observations of triggered seismicity and tremor to the tectonic environment to test the hypothesis that triggering and tremor most commonly occurs in volcanic and geothermal areas.

  17. Direct Correlation Between Film Structure and Solar Cell Efficiency for HWCVD Amorphous Silicon Germanium Alloys

    SciTech Connect

    Mahan, A. H.; Xu, Y.; Gedvilas, L. M.; Williamson, D. L.

    2009-01-01

    The film structure and H bonding of high deposition rate a-SiGe:H i-layers, deposited by HWCVD and containing {approx}40 at.% Ge, have been investigated using deposition conditions which replicate those used in n-i-p solar cell devices. Increasing the germane source gas depletion in HWCVD causes not only a decrease in solar cell efficiency from 8.64% to less than 7.0%, but also an increase in both the i-layer H preferential attachment ratio (PA) and the film microstructure fraction (R{sup {sq_bullet}}). Measurements of the XRD medium range order over a wide range of germane depletion indicate that this order is already optimum for the HWCVD i-layers, suggesting that energetic bombardment of a-SiGe:H films may not always be necessary to achieve well ordered films. Preliminary structural comparisons are also made between HWCVD and PECVD device layers.

  18. Quadruple-junction solar cells and modules based on amorphous and microcrystalline silicon with high stable efficiencies

    NASA Astrophysics Data System (ADS)

    Kirner, Simon; Neubert, Sebastian; Schultz, Christof; Gabriel, Onno; Stannowski, Bernd; Rech, Bernd; Schlatmann, Rutger

    2015-08-01

    Quadruple junction solar cells and modules are presented, which consist of hydrogenated amorphous (a-Si:H) and microcrystalline silicon (µc-Si:H) in the a-Si:H/a-Si:H/µc-Si:H/µc-Si:H configuration. The highest measured conversion efficiency of a mini-module with an aperture area of 61.44 cm2 was 13.4% before and 12.0% after more than 1000 h of light soaking, respectively. In this paper, we discuss the advantages of the quadruple junction design over the common tandem design, which is ascribed mainly to the fact that the total absorber thickness can be increased while electronic properties and stability are maintained or even improved. The role of the µc-SiOx:H intermediate reflector is highlighted and an optimization of the doping concentration in this layer is presented. Furthermore, the advantage of the high maximum power voltage for the monolithic cell interconnection laser design of modules is shown.

  19. Research on stable, high-efficiency amorphous silicon multijunction modules. Annual subcontract report, 1 December 1991--31 October 1992

    SciTech Connect

    Ghosh, M.; DelCueto, J.: Kampas, F.; Xi, J.

    1993-02-01

    This report describes results from the first phase of a three-phase contract for the development of stable, high-efficiency, same-band-gap, amorphous silicon (a-Si) multijunction photovoltaic (PV) modules. The program involved improving the properties of individual layers of semiconductor and non-semiconductor materials and small-area single-junction and multijunction devices, as well as the multijunction modules. The semiconductor materials research was performed on a-Si p, i, and n layers, and on microcrystalline silicon n layers. These were deposited using plasma-enhanced chemical vapor deposition. The non-semiconductor materials studied were tin oxide, for use as a transparent-conducting-oxide (TCO), and zinc oxide, for use as a back reflector and as a buffer layer between the TCO and the semiconductor layers. Tin oxide was deposited using atmospheric-pressure chemical vapor deposition. Zinc oxide was deposited using magnetron sputtering. The research indicated that the major challenge in the fabrication of a-Si multijunction PV modules is the contact between the two p-i-n cells. A structure that has low optical absorption but that also facilitates the recombination of electrons from the first p-i-n structure with holes from the second p-i-n structure is required. Non-semiconductor layers and a-Si semiconductor layers were tested without achieving the desired result.

  20. High-efficiency p-i-n superstrate amorphous Si solar cells on SiO x periodic arrays of three-dimensional microstructure prepared by soft imprinting

    NASA Astrophysics Data System (ADS)

    Niikura, Chisato; Chowdhury, Amartya; Janthong, Bancha; Sichanugrist, Porponth; Konagai, Makoto

    2016-04-01

    Efficient amorphous Si thin-film solar cells in a p-i-n superstrate configuration with a high initial conversion efficiency of 10.3% were successfully fabricated on periodically three-dimensional (3D) micropatterned SiO x /glass substrates prepared by soft imprinting. Conformal film deposition on a 3D microstructure was realized owing to the shape of our newly designed 3D pattern and the triode plasma-enhanced CVD technique, which enables the selective transport of favorable film precursors to the substrate surface. The nanoscale surface texture of the front transparent conductive oxide layer was found to be crucial for optical confinement, unexceptionally for amorphous Si solar cells on a 3D microstructure, which results in an improved short-circuit current density.

  1. Electrostatic Modeling of Vacuum Insulator Triple Junctions

    SciTech Connect

    Tully, L K; White, A D; Goerz, D A; Javedani, J B; Houck, T L

    2007-08-13

    A comprehensive matrix of 60 tests was designed to explore the effect of calcium chloride vs. sodium chloride and the ratio R of nitrate concentration over chloride concentration on the repassivation potential of Alloy 22. Tests were conducted using the cyclic potentiodynamic polarization (CPP) technique at 75 C and at 90 C. Results show that at a ratio R of 0.18 and higher nitrate was able to inhibit the crevice corrosion in Alloy 22 induced by chloride. Current results fail to show in a consistent way a different effect on the repassivation potential of Alloy 22 for calcium chloride solutions than for sodium chloride solutions.

  2. Amorphous Inorganic Electron-Selective Layers for Efficient Perovskite Solar Cells: Feasible Strategy Towards Room-Temperature Fabrication.

    PubMed

    Wang, Kai; Shi, Yantao; Li, Bo; Zhao, Liang; Wang, Wei; Wang, Xiangyuan; Bai, Xiaogong; Wang, Shufeng; Hao, Ce; Ma, Tingli

    2016-03-01

    Inorganic electron-selective layers (ESLs) are fabricated at extremely low temperatures of 70°C or even 25°C by a simple solution route. This is of great significance because the attained PCEs confirm the feasibility of room-temperature coating of inorganic amorphous ESLs through a solution method for the first time. PMID:26708492

  3. Porous one-dimensional Mo2C-amorphous carbon composites: high-efficient and durable electrocatalysts for hydrogen generation.

    PubMed

    Zhang, Kai; Li, Chunyan; Zhao, Yang; Yu, Xianbo; Chen, Yujin

    2015-07-01

    Porous one-dimensional Mo2C-amorphous carbon composites, fabricated by in situ solid state reactions, are exhibited as effective and high-performance electrocatalysts towards the hydrogen evolution reaction (HER). The morphological and structural characteristics of the Mo2C based electrocatalysts were analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). The analyses showed that they had various advantages for the HER, including a high crystallinity, porous and tubular characteristics and good conductivity. The porous one-dimensional Mo2C-amorphous carbon composites with a larger content of Mo2C and moderate thickness of the carbon layers exhibited superior catalytic activities for HER to most of the Mo2C based electrocatalysts recently reported. PMID:26055048

  4. Neogene Structural Basins Beneath Santa Rosa Plain: Strike-Slip Basins Formed in Wake of the Mendocino Triple Junction During Initiation of the Rodgers Creek-Healdsburg Fault Zone

    NASA Astrophysics Data System (ADS)

    McLaughlin, R. J.; Sarna-Wojcicki, A. M.; Fleck, R. J.; Langenheim, V. E.; McPhee, D. K.; Jachens, R. C.; Wagner, D. L.; McCabe, C. A.

    2006-12-01

    Located on the Humboldt Plate, just N of the San Francisco Bay block, the Santa Rosa Plain (SRP) is a NW- oriented dissected lowland ~60 km long by 12 km wide, underlain by fault bounded Neogene basins containing syntectonic sedimentary and volcanic fills up to 2.5 km-thick. In response to lengthening of the transform margin ~7 to 5 Ma, Neogene strata now beneath the plain were dropped into extensional basins in a SE-tapered wedge-shaped block bounded on the SW by ~N 50° W-oriented faults of a proto-Hayward fault zone, and on the NE by newly initiated ~N 35°- 40°W-oriented faults of the Rodgers Creek-Healdsburg fault zone. Comparisons of the geologic, chronostratigraphic and geophysical frameworks of SRP with well constrained datasets used for Neogene reconstructions of the northern San Andreas Fault system indicates to us that the SRP and its buried basins are firmly tied to a strike-slip basin formational setting in the wake of the Mendocino triple junction (MTJ). Onshore and offshore datasets that integrate the geology and chronostratigraphy with geophysical data show that the MTJ at ~7 to 5 Ma was situated between the present latitudes of ~38.5° and ~39° N, opposite SRP. The SRP formed the delta of a large river that flowed toward the WNW, around a proto-Hayward fault-bounded bedrock promontory, into an estuary that adjoined the adjacent near shore and shelf of the margin. The modern Eel River basin, a deformed and uplifted remnant of the Cascadia Forearc margin just north of the present position of the MTJ, lies in a setting similar to the paleogeographic setting of the SRP. Closer examination, however, reveals two important differences between the SRP and MTJ settings. First, the ~6 to 9 Ma fluvial system that flowed NW across the Hayward fault from the east San Francisco Bay region onto SRP, also flowed across the San Andreas fault into submarine canyons of the Delgada Fan on the Pacific Plate, south of the MTJ. In contrast, sediment transported by the

  5. An efficient light trapping scheme based on textured conductive photonic crystal back reflector for performance improvement of amorphous silicon solar cells

    NASA Astrophysics Data System (ADS)

    Chen, Peizhuan; Hou, Guofu; Fan, QiHua; Huang, Qian; Zhao, Jing; Zhang, Jianjun; Ni, Jian; Zhang, Xiaodan; Zhao, Ying

    2014-08-01

    An efficient light trapping scheme named as textured conductive photonic crystal (TCPC) has been proposed and then applied as a back-reflector (BR) in n-i-p hydrogenated amorphous silicon (a-Si:H) solar cell. This TCPC BR combined a flat one-dimensional photonic crystal and a randomly textured surface of chemically etched ZnO:Al. Total efficiency enhancement was obtained thanks to the sufficient conductivity, high reflectivity and strong light scattering of the TCPC BR. Unwanted intrinsic losses of surface plasmon modes are avoided. An initial efficiency of 9.66% for a-Si:H solar cell was obtained with short-circuit current density of 14.74 mA/cm2, fill factor of 70.3%, and open-circuit voltage of 0.932 V.

  6. An efficient light trapping scheme based on textured conductive photonic crystal back reflector for performance improvement of amorphous silicon solar cells

    SciTech Connect

    Chen, Peizhuan; Hou, Guofu Huang, Qian; Zhao, Jing; Zhang, Jianjun Ni, Jian; Zhang, Xiaodan; Zhao, Ying; Fan, QiHua

    2014-08-18

    An efficient light trapping scheme named as textured conductive photonic crystal (TCPC) has been proposed and then applied as a back-reflector (BR) in n-i-p hydrogenated amorphous silicon (a-Si:H) solar cell. This TCPC BR combined a flat one-dimensional photonic crystal and a randomly textured surface of chemically etched ZnO:Al. Total efficiency enhancement was obtained thanks to the sufficient conductivity, high reflectivity and strong light scattering of the TCPC BR. Unwanted intrinsic losses of surface plasmon modes are avoided. An initial efficiency of 9.66% for a-Si:H solar cell was obtained with short-circuit current density of 14.74 mA/cm{sup 2}, fill factor of 70.3%, and open-circuit voltage of 0.932 V.

  7. Multi-functional stacked light-trapping structure for stabilizing and boosting solar-electricity efficiency of hydrogenated amorphous silicon solar cells

    NASA Astrophysics Data System (ADS)

    Huang, Wen-Hsien; Shieh, Jia-Min; Pan, Fu-Ming; Shen, Chang-Hong; Huang, Jung Y.; Wu, Tsung-Ta; Kao, Ming-Hsuan; Hsiao, Tzu-Hsuan; Yu, Peichen; Kuo, Hao-Chung; Lee, Ching-Ting

    2013-08-01

    A sandwiched light-trapping electrode structure, which consists of a capping aluminum-doped ZnO (AZO) layer, dispersed plasmonic Au-nanoparticles (Au-NPs), and a micro-structured transparent conductive substrate, is employed to stabilize and boost the conversion-efficiency of hydrogenated amorphous silicon (a-Si:H) solar cells. The conformal AZO ultrathin layer (5 nm) smoothened the Au-NP-dispersed electrode surface, thereby reducing defects across the AZO/a-Si:H interface and resulting in a high resistance to photo-degradation in the ultraviolet-blue photoresponse band. With the plasmonic light-trapping structure, the cell has a high conversion-efficiency of 10.1% and the photo-degradation is as small as 7%.

  8. High-Efficiency Polycrystalline CdTe Thin-Film Solar Cells with an Oxygenated Amorphous CdS (a-CdS:O) Window Layer: Preprint

    SciTech Connect

    Wu, X.; Dhere, R. G.; Yan, Y.; Romero, M. J.; Zhang, Y.; Zhou, J.; DeHart, C.; Duda, A.; Perkins, C.; To, B.

    2002-05-01

    In the conventional CdS/CdTe device structure, the poly-CdS window layer has a bandgap of {approx}2.4 eV, which causes absorption in the short-wavelength region. Higher short-circuit current densities (Jsc) can be achieved by reducing the CdS thickness, but this can adversely impact device open-circuit voltage (Voc) and fill factor (FF). Also, poly-CdS film has about 10% lattice mismatch related to the CdTe film, which limits the improvement of device Voc and FF. In this paper, we report a novel window material: oxygenated amorphous CdS film (a-CdS:O) prepared at room temperature by rf sputtering. The a-CdS:O film has a higher optical bandgap (2.5-3.1 eV) than the poly-CdS film and an amorphous structure. The preliminary device results have demonstrated that Jsc of the CdTe device can be greatly improved while maintaining higher Voc and FF. We have fabricated a CdTe cell demonstrating an NREL-confirmed Jsc of 25.85 mA/cm2 and a total-area efficiency of 15.4%.

  9. Amorphous Fe²⁺-rich FeOx loaded in mesoporous silica as a highly efficient heterogeneous Fenton catalyst.

    PubMed

    Wang, Min; Shu, Zhu; Zhang, Lingxia; Fan, Xiangqian; Tao, Guiju; Wang, Yongxia; Chen, Lisong; Wu, Meiying; Shi, Jianlin

    2014-06-28

    A simple physical-vapor-infiltration (PVI) method using ferrocene as the iron source, has been developed to load FeOx into the pore channels of mesoporous silica SBA-15. The obtained FeOx/SBA-15 composite has a high loading amount of FeOx (e.g. 26.64 wt% Fe content obtained at PVI duration 17 h and calcination temperature 450 °C) but unblocked pore channels thanks to the unique preparation strategy. The FeOx species are amorphous, rich of Fe(2+) and have been highly dispersed as a nanocoating onto the pore channel surface. The FeOx/SBA-15 composite was used as a heterogeneous Fenton catalyst to degrade Acid orange 7 (AO7). It showed a high catalytic activity and degradation efficiency, which was attributed to the high proportion of Fe(2+) in the amorphous FeOx and their favorable adsorption capability for the dye. The influences of the PVI duration, the calcination temperature and the Fenton reaction conditions (FeOx/SBA-15 dosages, H2O2 dosages and initial pH value) on the catalytic activity were investigated in detail. PMID:24816279

  10. Amorphous silicon photovoltaic devices

    SciTech Connect

    Carlson, David E.; Lin, Guang H.; Ganguly, Gautam

    2004-08-31

    This invention is a photovoltaic device comprising an intrinsic or i-layer of amorphous silicon and where the photovoltaic device is more efficient at converting light energy to electric energy at high operating temperatures than at low operating temperatures. The photovoltaic devices of this invention are suitable for use in high temperature operating environments.