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Physicochemical Characterization of Porous Silicon Surfaces Etched in Salt Solutions of Varying Compositions and pH

Published online by Cambridge University Press:  01 February 2011

Mariem Rosario-Canales
Affiliation:
University of Puerto Rico, Río Piedras Campus, Department of Chemistry, P.O. Box 23346, San Juan, Puerto Rico, 00931-3346
Ana R. Guadalupe
Affiliation:
University of Puerto Rico, Río Piedras Campus, Department of Chemistry, P.O. Box 23346, San Juan, Puerto Rico, 00931-3346
Luis F. Fonseca
Affiliation:
University of Puerto Rico, Río Piedras Campus, Department of Physics, P.O. Box, 23343, San Juan, Puerto Rico, 00931-3343
Oscar Resto
Affiliation:
University of Puerto Rico, Río Piedras Campus, Department of Physics, P.O. Box, 23343, San Juan, Puerto Rico, 00931-3343
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Abstract

We prepared porous silicon (PSi) structures by standard electrochemical processes using aqueous sodium fluoride (NaF) solutions. We report the dependence of the porous structure on the variation of pH and salt concentration of the etching solution, and the applied current density. The PSi structures were characterized by Scanning Electron Microscopy (SEM) and Secondary Ion Mass Spectroscopy (SIMS) to determine the pore size and distribution and the surface chemical composition. Results obtained from SEM show that the PSi grown has two different structures depending on the current density. Low current densities produce a uniform, high-density arrangement of pores while high current densities yield a sponge-like structural network. SIMS results indicate that the porous framework is covered with a silicon oxide layer.

Type
Research Article
Copyright
Copyright © Materials Research Society 2003

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