Porous silicon: electrochemical microstructuring, photoluminescence, and covalent modificaiton

Maxim B. Prigozhin; Pauline Shiwsankar; W. Russ Algar; Ulrich J. Krull

doi:10.1117/12.807175

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12 August 2008 Porous silicon: electrochemical microstructuring, photoluminescence, and covalent modificaiton

Maxim B. Prigozhin, Pauline Shiwsankar, W. Russ Algar, Ulrich J. Krull

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Proceedings Volume 7099, Photonics North 2008; 70991A (2008) https://doi.org/10.1117/12.807175
Event: Photonics North 2008, 2008, Montréal, Canada

Abstract

Interest in porous silicon (PS) has increased dramatically over the past two decades due to aspects such as photoluminescence due to quantum confinement, large surface area, and micro/nanoscale architecture. In this work, <111> p-type silicon wafers have been electrochemically etched with ethanolic solutions of hydrofluoric acid. Discrete surface domains showing luminescence were observed. The domains were typically many tens of micrometers in size and had a height of about 6-8 μm. Interestingly, central round wells of 10-30 μm diameter were observed to form within domains. Investigation of luminescence in depth profile of the wells was done using confocal fluorescence microscopy, and the results indicated that the domains were fully porous and luminescent throughout the entire depth. Spectrally, the peak fluorescence emission was in the range of 550-750 nm and the spectra had an average FWHM equal to about 150 nm. Covalent attachment of organic monolayers to the porous silicon surfaces was done to try and passivate against oxidation, and also to explore the possibilities of bioconjugation and tuning of the photoluminescence wavelength. A reaction of hydrogen terminated silicon with ω-undecylenyl alcohol was done using irradiation by a UV source, and successful derivatization was confirmed with IR spectroscopy. Bulk electrochemical etching of silicon provided a method to generate distributed luminescent structures suitable for compartmentalization of reactions within wells of micrometer dimensions without the use of spatially resolved fabrication methodologies such as epitaxial deposition, lithography, or ion beam technologies.

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Maxim B. Prigozhin, Pauline Shiwsankar, W. Russ Algar, and Ulrich J. Krull "Porous silicon: electrochemical microstructuring, photoluminescence, and covalent modificaiton", Proc. SPIE 7099, Photonics North 2008, 70991A (12 August 2008); https://doi.org/10.1117/12.807175

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