The Experts below are selected from a list of 357255 Experts worldwide ranked by ideXlab platform
A. Catalano - One of the best experts on this subject based on the ideXlab platform.
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Polycrystalline thin-film technologies: Status and prospects
Solar Energy Materials and Solar Cells, 1996Co-Authors: A. CatalanoAbstract:Abstract The recent progress towards high-efficiency thin-film Polycrystalline solar cells is examined in this paper together with a brief history of their development. We focus on the three materials of contemporary interest for such devices: Polycrystalline Si, CuInSe 2 and its alloys, and CdTe. Although there has often been an implicit assumption that thin-film devices required a compromise of lower efficiency than their single, or bulk Polycrystalline competitors, we now see for the first time that Polycrystalline thin-film solar cells can rival these devices. In dispelling this myth, we examine the elements that have contributed to the progress in each area.
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Polycrystalline thin-film technologies: status and prospects
Proceedings of 1994 IEEE 1st World Conference on Photovoltaic Energy Conversion - WCPEC (A Joint Conference of PVSC PVSEC and PSEC), 1Co-Authors: A. CatalanoAbstract:The progress towards high-efficiency thin-film Polycrystalline solar cells is examined in this paper together with a brief history of their development. We focus on the three materials of contemporary interest for such devices: Polycrystalline Si, CuInSe/sub 2/ and its alloys, and CdTe. Although there has often been an implicit assumption that thin-film devices required a compromise of lower efficiency than their single-crystal, or bulk Polycrystalline competitors, we now see, for the first time, that Polycrystalline thin-film solar cells can rival these devices. In dispelling this myth, we examine the elements that have contributed to the progress in each area.
Jinki Hong - One of the best experts on this subject based on the ideXlab platform.
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Schottky-type Polycrystalline CdZnTe X-ray detectors
Current Applied Physics, 2009Co-Authors: Jinki HongAbstract:Abstract The Polycrystalline CdZnTe:Cl thick films which have high resistivity about 5 × 10 9 Ω cm are grown by thermal evaporation method. The leakage currents of as-deposited CdZnTe layers are still too high to operate as medical applications. The blocking layer of Schottky type was formed on the stoichiometric surface of Polycrystalline CdZnTe layers to suppress the leakage current of Polycrystalline CdZnTe X-ray detectors. The Polycrystalline CdZnTe Schottky barrier diodes with indium contact exhibit the low leakage current (14 nA/cm 2 ) at 40 V due to its high barrier height ( ϕ b = 0.80 eV). In X-ray image acquisition with Schottky-type linear array Polycrystalline CdZnTe X-ray detector, we have obtained the promising results and proved the possibility of Polycrystalline CdZnTe for applications as a flat panel X-ray detector.
B Mantisi - One of the best experts on this subject based on the ideXlab platform.
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Generation of Polycrystalline material at the atomic scale
Computational Materials Science, 2016Co-Authors: B MantisiAbstract:Polycrystalline structure plays an important role in the macroscopic properties of a solid material. In this paper we propose a new code to generate a Polycrystalline material at the atomic scale. Our Polycrystalline systems are based on the random generation from initial germs. From a mechanical point of view, it brings new features as for example ductility of 3D Polycrystalline aluminum. By using molecular dynamics simulations, we also show the eect of temperature on a geological material, olivine, one of the most abundant silicate mineral of the Earth upper mantle. The importance of porous media is also considered (e.g. metals).
B Cunningham - One of the best experts on this subject based on the ideXlab platform.
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the thermal stability of cosi2 on Polycrystalline silicon the effect of silicon grain size and metal thickness
Journal of The Electrochemical Society, 1998Co-Authors: Jeffrey P Gambino, E G Colgan, A G Domenicucci, B CunninghamAbstract:The stability of CoSi 2 on Polycrystalline Si has been studied as a function of both the initial Si grain size and the initial silicide thickness. When the Si grain size is small (Si grain size « Polycrystalline Si thickness), CoSi 2 /Polycrystalline Si structures are unstable due to grain growth in the Polycrystalline Si. If the initial silicide is thick (silicide thickness = Polycrystalline Si thickness), nearly all the Si grains are consumed by the silicide and converted into large Si grains. The conversion of the Polycrystalline Si from small grains to large grains occurs first at the surface and then proceeds to the bottom interface, resulting in the inverted structures observed in earlier studies. Further annealing results in a quilt structure, with alternating grains of silicide and Polycrystalline Si that run through the thickness of the film. As the silicide thickness decreases (silicide thickness « Polycrystalline Si thickness), the grain growth in the Polycrystalline Si is mainly confined to the surface, with relatively few inverted grains. Fewer Si grains come in contact with the silicide due to the small volume fraction of the silicide, hence fewer Si grains are converted to large grains. As the initial grain size of the starting Polycrystalline Si increases, the CoSi 2 /Polycrystalline Si structures become more stable because the driving force for Si grain growth decreases. Relatively few Si grains show enhanced grain growth. As the metal thickness decreases, the silicide becomes less stable due to agglomeration of the silicide on the large grain Polycrystalline Si. Hence, the driving force for the instability changes from grain growth in the Si to minimization of interface and surface energy of the silicide.
Tetsuo Irifune - One of the best experts on this subject based on the ideXlab platform.
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Superhard Polycrystalline {\gamma}-boron
arXiv: Materials Science, 2012Co-Authors: Jiaqian Qin, Norimasa Nishiyama, Hiroaki Ohfuji, Toru Shinmei, Li Lei, Tetsuo IrifuneAbstract:The Vickers hardness of Polycrystalline {\gamma}-B was measured using a diamond indentation method. The elastic properties of Polycrystalline {\gamma}-B (B=213.9 GPa, G=227.2 GPa, and E=503.3 GPa) were determined using ultrasonic measurement at ambient condition. Under the loading force up to 20 N, our test gave an average Vickers hardness in the asymptotic-hardness region of 30.3 GPa. The average fracture toughness was measured as 4.1MPa m1/2. Additionally, We also measured the hardness and elastic properties of Polycrystalline {\beta}-B and PcBN for comparison. The hardness and elastic properties for Polycrystalline {\gamma}-B was found to be very close to that of PcBN. Our results suggest that the Polycrystalline {\gamma}-B could be a superhard Polycrystalline material for industrial applications.
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Polycrystalline γ-boron: As hard as Polycrystalline cubic boron nitride
Scripta Materialia, 2012Co-Authors: Jiaqian Qin, Norimasa Nishiyama, Hiroaki Ohfuji, Toru Shinmei, Li Lei, Tetsuo IrifuneAbstract:The Vickers hardness of Polycrystalline γ-boron (γ-B) was measured using a diamond indentation method. The elastic properties of Polycrystalline γ-B were determined using an ultrasonic measurement method. Under a loading force of up to 20 N our test gave an average Vickers hardness in the asymptotic hardness region around 30.3 GPa. We also measured the hardness and elastic properties of Polycrystalline β-B and cubic boron nitride–Ti 3 SiC 2 (PcBN) for comparison. The hardness and elastic properties of Polycrystalline γ-B were found to be very close to those of PcBN.
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Microstructure and Mechanical Behaviors of Nano-Polycrystalline Diamonds Synthesized by Direct Conversion Sintering under HPHT
MRS Proceedings, 2011Co-Authors: Hitoshi Sumiya, Tetsuo IrifuneAbstract:AbstractHigh-purity nano-Polycrystalline diamonds have been synthesized by direct conversion from graphite and various non-graphitic carbons under static high pressures and high temperatures. The Polycrystalline diamond synthesized from graphite at ≥15 GPa and 2300-2600 °C has a mixed texture comprising a homogeneous fine structure (particle size: 10-30 nm, formed in a diffusion process) and a lamellar structure (formed in a martensitic process), and has a very high Knoop hardness of 120-145 GPa. In contrast, the Polycrystalline diamonds made from the non-graphitic carbons at ≥15 GPa and 1600-2000 °C have a single texture consisting of a very fine homogeneous structure (5-10 nm, formed in a diffusion process) without a lamellar structure. The hardness values of the nano-Polycrystalline diamonds made from non-graphitic carbons (70-90 GPa) are significantly lower than that of Polycrystalline diamond made from graphite. The investigation of the microstructure beneath the indentation of these nano-Polycrystalline diamonds revealed that the existence of the lamellar structure and the bonding strength of the grain boundary have a decisive effect on the hardness.
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Hardness and deformation microstructures of nano-Polycrystalline diamonds synthesized from various carbons under high pressure and high temperature
Journal of Materials Research, 2007Co-Authors: Hitoshi Sumiya, Tetsuo IrifuneAbstract:Mechanical properties of high-purity nano-Polycrystalline diamonds synthesized by direct conversion from graphite and various non-graphitic carbons under static high pressures and high temperatures were investigated by microindentation testing with a Knoop indenter and observation of microstructures around the indentations. Results of indentation hardness tests using a superhard synthetic diamond Knoop indenter showed that the Polycrystalline diamond synthesized from graphite at ⩾15 GPa and 2300–2500 °C (consisting of fine grains 10–30 nm in size and layered crystals) has very high Knoop hardness (Hk ⩾ 110 GPa), whereas the hardness of Polycrystalline diamonds synthesized from non-graphitic carbons at ⩾15 GPa and below 2000 °C (consisting only of single-nano grains 5–10 nm in size) are significantly lower (Hk = 70 to 90 GPa). Microstructure observations beneath the indentations of these nano-Polycrystalline diamonds suggest that the existence of a lamellar structure and the bonding strength of the grain boundary play important roles in controlling the hardness of the Polycrystalline diamond.
