The Surface Chemistry of Silicon in Fluoride Electrolytes

Searson, Peter C.

doi:10.1002/9783527616787.ch2

Cited by 8 publications

(2 citation statements)

References 135 publications

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“…Porous silicon can be prepared by chemical or electrochemical etching processes and consists of nano- or microcrystalline domains with defined pore morphologies. The diameter, geometric shape, and direction of the pores depend on surface orientation, doping level and type, temperature, the composition of the etching solution, and the current density. , Porous silicon has been employed as a large surface area matrix for immobilization of a variety of biomolecules including enzymes, DNA fragments, and antibodies . Moreover, we recently showed that the electronic or optical properties of porous silicon can also be used as the transducer of biomolecular interactions, thus qualifying its utility in biosensor applications. , A Fabry−Perot fringe pattern is created by multiple reflections of illuminated white light on the air−porous silicon layer and the porous silicon−bulk silicon interface.…”

Section: Introductionmentioning

confidence: 99%

Macroporous p-Type Silicon Fabry−Perot Layers. Fabrication, Characterization, and Applications in Biosensing

et al. 1998

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We present in this paper that porous silicon can be used as a large surface area matrix as well as the transducer of biomolecular interactions. We report the fabrication of heavily doped p-type porous silicon with pore diameters that can be tuned, depending on the etching condition, from approximately 5 to 1200 nm. The structure and porosity of the matrixes were characterized by scanning force microscopy (SFM) and scanning electron microscopy (SEM), Brunnauer-Emmett-Teller nitrogen adsorption isotherms, and reflectance interference spectroscopy. The thin porous silicon layers are transparent to the visible region of the reflectance spectra due to their high porosity (80-90%) and are smooth enough to produce Fabry-Perot fringe patterns upon white light illumination. Porous silicon matrixes were modified by ozone oxidation, functionalized in the presence of (2-pyridyldithiopropionamidobutyl)dimethylmethoxysilane, reduced to unmask the sulfhydryl functionalities, and coupled to biotin through a disulfide-bond-forming reaction. Such functionalized matrixes display considerable stability against oxidation and corrosion in aqueous media and were used to evaluate the utility of porous silicon in biosensing. The streptavidin-biotin interactions on the surface of porous silicon could be monitored by the changes in the effective optical thickness calculated from the observed shifts in the Fabry-Perot fringe pattern caused by the change in the refractive index of the medium upon protein-ligand binding. Porous silicon thus combines the properties of a mechanically and chemically stable high surface area matrix with the function of an optical transducer and as such may find utility in the fabrication of biosensor devices.

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Section: Introductionmentioning

confidence: 99%

Macroporous p-Type Silicon Fabry−Perot Layers. Fabrication, Characterization, and Applications in Biosensing

et al. 1998

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“…The complex details of these reactions can be found in various published models. − Reaction 1 occurs in the potential region U ocp < U Si < U peak , where U ocp is the open circuit potential and U peak is the potential at the first characteristic peak found in the anodic voltammogram of the Si/aqueous HF system. This region is characterized by low current densities and applied potentials.…”

Section: Resultsmentioning

confidence: 99%

All-Electrochemical Synthesis of Submicrometer Cu Structures on Electrochemically Machined p-Si Substrates

et al. 2005

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A maskless all-electrochemical method for the deposition of micro-and nanoscale Cu structures on p-Si is reported. The first step involves the electrochemical machining of p-type Si in HF by applying nanosecond voltage pulses between a tool and a Si electrode. This process generates a localized defect structure, which is successively utilized to achieve selective metal electrodeposition. The resolution of the process is limited mainly by the tool dimensions and by the time constants involved in electrochemical machining, which lead to a limited spread of the defect region on the Si surface. Copper isolated islands with 500 nm diameter have been grown by electrodeposition, with high selectivity. This process has the potential to become a preferred technique for the placement and growth of submicrometer metal islands on semiconductor surfaces.

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