Nucleation and Growth of Cu Adsorbates on Hydrogen-Terminated Si(111) Surface in Solution

Hara, K.; Tanii, Takashi; Ohdomari, Iwao

doi:10.1143/jjap.38.6860

Cited by 5 publications

(2 citation statements)

References 13 publications

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“…23, that copper prefers to adsorb at dihydride rather than monohydride sites on the surface, agrees with our results and supports experiments studying copper nucleation. [40][41][42][43][44] These calculations are part of a larger effort to include the role of metal impurities in a multiscale model of anisotropic wet chemical etching. Although a quantitative comparison with etching experiments still requires full integration of these results into mesoscale simulations, we can compare the general trends.…”

Section: Discussionmentioning

confidence: 99%

First-principles calculations of Cu adsorption on an H-terminated Si surface

et al. 2007

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In this study, we use first-principles simulations to study the adsorption of copper onto H-terminated and partially OH-terminated silicon surfaces. We show that, in contrast to previous studies, copper adsorbs strongly to the H-terminated silicon surface and that the adsorption energy is significantly dependent on the local bonding environment. The addition of a hydroxide group increases the average adsorption energy while reducing the range of adsorption energies due to the strong interaction between copper and oxygen. Our results predict that copper will generally prefer to adsorb at dihydride sites on the surface, agreeing with experimental studies of copper nucleation. The adsorption energy hierarchy predicted by the calculations strongly supports the suggestion that copper acts as a micromask in wet chemical etching, blocking reactive sites.

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Section: Discussionmentioning

confidence: 99%

First-principles calculations of Cu adsorption on an H-terminated Si surface

et al. 2007

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“…21 The metal formation process is accompanied by a gradual oxidation of the mesoporous layer and, thus, eventually limited by its complete pore wall oxidation. However, consistent experimental information on the chemical and physical processes occurring during spontaneous copper deposition is not available even though some theoretical 22,23 and experimental [24][25][26] efforts have been undertaken to elucidate metal deposition, in particular, copper formation, on PS. For example, Tatsumura et al 23 performed first-principle quantum chemical calculations to clarify the nucleation sites of Cu on H-terminated Si surfaces.…”

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confidence: 99%

Quenching of Reducing Properties of Mesoporous Silicon and Its Use as Template for Metal/Semiconductor Deposition

Kumar

Huber

2010

J. Electrochem. Soc.

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We report on a study of the formation of crystalline copper and nanocrystalline cuprous oxide ͑Cu 2 O͒ at electrochemically prepared mesoporous silicon surfaces immersed in a copper sulfate solution. The metal deposition on porous silicon, either by using the reducing properties of the as-prepared native mesoporous surface ͑immersion plating͒ or by applying an external current ͑electroplating͒, is investigated by IR spectroscopy, X-ray diffraction, and scanning electron microscopy. The degree of oxidation and the surface chemistry of the porous epilayers ͑porosity 50%, mean pore diameter 10 nm, and pore length 25 µm͒ are varied by annealing at different temperatures. For immersion plating, we observe the formation of face-centered cubic copper crystals with irregular shapes and a broad size distribution from the nano-to the micrometer scale. Electroplating of as-prepared porous layers leads to a crystalline copper film which homogeneously covers the porous silicon surface. By contrast, electroplating of partially oxidized porous layers leads to isolated single copper crystals with quadratic bipyramidal shape at the outer porous epilayer surface and a sizable fraction of nanochannel confined crystalline Cu 2 O, a prominent candidate for the investigation and application of quantum confinement effects in semiconductors.Porous silicon was discovered rather by chance than on purpose in the mid 1950s. 1 Its ability to exhibit photoluminescence at visible wavelengths at room temperature in contrast to bulk silicon was reported in 1990, 2 and could be rigorously traced to a certain defect class in the mesoporous silicon walls only recently. 3 Due to its peculiar optical and surface properties, PS has received much attention with regard to applications in light emitting diodes, 4 light testing equipment, 5 photoelectric solar batteries, 6 gas testing, 7 microsensors, 8 and biosensors. 9,10 It acts as an effective nucleationinducing material for protein solution crystallization 11 and, in general, is believed to be a biocompatible form of silicon. 12 Depending on the preparation procedure, the formation mechanisms allow for the variation of pore wall morphology and chemistry over a wide range. 13,14 Therefore, it is also particularly suitable to study the fundamental equilibrium and transport properties of pore-condensed matter, e.g., capillary condensation phenomena, freezing and melting transitions, as well as molecular gas flow and magnetic properties, as a function of the geometry of the employed mesoporous templates. [15][16][17] More than 10 years ago, it was found that PS also has peculiar electrochemical properties. It acts as a modest reducing agent. 18 However, much less attention has been paid to using PS as both a reducing agent and a substrate for metal deposition. Such an application would allow for an elegant preparation of metal/ semiconductor contacts, which is crucial for electroluminescent devices. 19 Porous silicon/metal composite electrodes could also enhance the electrocatalytic activity of photoelec...

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Nucleation and growth of copper on mesoporous silicon by immersion plating

Kumar¹,

Huber²

2007

J. Phys. D: Appl. Phys.

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Copper deposition was investigated on electrochemically etched mesoporous silicon epilayers of pore diameter 7 nm, porosity 45% and surface area 500 m2 cm−3 by immersion plating in an aqueous solution containing Cu2+ ions. When the layers were immersed in a 0.1 M CuSO4 · 5H2O aqueous solution for different time-periods ranging from 1 to 60 min, elemental copper was deposited on the surface. Fourier transform infrared (FTIR) spectroscopy in transmittance mode was carried out on copper deposited porous silicon (PS) samples to infer the changes in the surface bonding of the PS. It was clearly observed from x-ray diffraction patterns and FTIR spectra that the reduction of copper ion on PS was accompanied by gradual and finally complete oxidation of the PS epilayers surface. Scanning electron microscopy has been used to study the morphology of the copper aggregates at the PS epilayers surface.

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Nucleation and Growth of Cu Adsorbates on Hydrogen-Terminated Si(111) Surface in Solution

Cited by 5 publications

References 13 publications

First-principles calculations of Cu adsorption on an H-terminated Si surface

First-principles calculations of Cu adsorption on an H-terminated Si surface

Quenching of Reducing Properties of Mesoporous Silicon and Its Use as Template for Metal/Semiconductor Deposition

Nucleation and growth of copper on mesoporous silicon by immersion plating

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