Papers by Keyword: Silicon Nanoparticles

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Authors: Vladimir Baturin, Sergey Lepeshkin, Nikita Matsko, Yurii Uspenskii
Abstract: The total energy, geometry and electronic spectra of nanoclusters \shm{} ($m=0\ldots11$) are calculated using the evolutionary algorithm and density functional theory (DFT). It is shown, that the features of electron spectrum, namely HOMO-LUMO gap and valence band width, correlate with cluster geometry and stability. The HOMO-LUMO gap becomes wider as the number of hydrogen atoms increases whereas the width of valence band gets lower. The widening of the band gap indicates the increasing of cluster stability which is consistent with existing data on reaction energy.
Authors: Antonela Dima, Massimo Gagliardi, Dun Liu, Walter Perrie, Craig J. Williams, Ivo Rendina, Geoff Dearden, Ken G. Watkins
Abstract: Patterned structures were created by exposing SiO2 sol-gel films containing nano-silicon particles to a Clark MXR CPA-2010 fs laser (387 nm). A refractive index variation of 0.2 was obtained, similar to that of polymer films, however in an entirely superior stability class (structural, chemical, thermal, radiation, etc). The useful optical range of refractive index modulation is beyond 800 nm, respectively near-IR. Material characteristics were investigated with atomic force microscopy (AFM), Raman spectroscopy and spectro-ellipsometry measurements. Material properties were also investigated on different substrates in order to determine the influence of substrate type in laser processing.
Authors: Ahmad Farooq, Ali Abd El-Aty
Abstract: Silica coated alumina abrasives, used for abrading the surface of Yttria stabilized tetragonal zirconia polycrystal ceramics, were produced in order to achieve successful bonding with resin luting cement. The source of the silica coating was from Silicon Nanoparticles (SiNPs) that were produced from spark erosion in high pressure flushing of deionized water. SEM images verified average size distribution of the SiNPs to be between 30-50nm. In contrast to the tribochemical methods that are used widely to produce such abrasives, a completely novel dry physical process was opted for this experiment. By optimization of the conditions, 2g of purified SiNPs was mixed with 20g of alumina μ-particles (approximated diameter of 100μm), in presence of 25ml ethanol, mixed thoroughly to form slurry. Heated up to 120°C for 20 minutes to evaporate the ethanol, the resultant powder mix was compacted and uploaded in furnace at temperature of 1100°C for 2hrs. This formed an oxide layer on the SiNPs which consequently formed bonding with the alumina particles. SEM/EDS results validate substantial amount of coating of silica on alumina. The paper hereby demonstrates a novel method of producing silica coated alumina abrasives, which is a dry and cleaner substitution method compared to tribochemical approach.
Authors: Jeong Boon Koo, Chun Young Jung, Bo Yun Jang
Abstract: Phosphorous (P) incorporated silicon nanoparticles (Si NPs) were synthesized by using inductive coupled plasma (ICP) and a specially designed double tube reactor.Their microstructures were investigated by injecting various amounts of PH3 gas during the synthesis. Injection of PH3 gas during the synthesis resulted in a change from crystalline to amorphous phase, a reduction of particle size as well as process yield. These results were attributed to a lower plasma density when higher amount of PH3 was injected.From EDS, SIMS and XPS analysis, it was revealed that P was successively incorporated in Si NPs.However, secondary phases such as P4 (red P) and P2O5were formed as amorphous ones in nanoscale when a relatively large amount of PH3 was injected.
Authors: Xian Gao Zhang, Xi Gen Miao, Zhi Ya Zhao, Ruo Peng Liu, Ming Yu Li
Abstract: Nanostructure strategies are frequently used to enhance the light absorption in solar cells. For improving the efficiency of absorption in solar cells, an industrial-feasible processing technique, i.e. low-pressure chemical vapor deposition was used to form a substrate with large-area silicon nanoparticles (Si-NPs). It was shown that the density and size of Si-NPs can be modulated by controlling the flow of pure SiH4, the deposition temperature and the deposition time. The substrate with large-area Si-NPs can be applied in photovoltaic devices since they can increase the effective absorption path of the incident sunlight.
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