Cisneros, Rodolfo and Pfeiffer, Heriberto and Wang, Chumin (2010) Oxygen Absorption in Free-Standing Porous Silicon: A Structural, Optical and Kinetic Analysis. Nanoscale Research Letters, 5 (4). pp. 686-691.
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Official URL: http://www.springerlink.com/content/6325h225u836x3...
Porous silicon (PSi) is a nanostructured material possessing a huge surface area per unit volume. In consequence, the adsorption and diffusion of oxygen in PSi are particularly important phenomena and frequently cause significant changes in its properties. In this paper, we study the thermal oxidation of p +-type free-standing PSi fabricated by anodic electrochemical etching. These free-standing samples were characterized by nitrogen adsorption, thermogravimetry, atomic force microscopy and powder X-ray diffraction. The results show a structural phase transition from crystalline silicon to a combination of cristobalite and quartz, passing through amorphous silicon and amorphous silicon-oxide structures, when the thermal oxidation temperature increases from 400 to 900 °C. Moreover, we observe some evidence of a sinterization at 400 °C and an optimal oxygen-absorption temperature about 700 °C. Finally, the UV/Visible spectrophotometry reveals a red and a blue shift of the optical transmittance spectra for samples with oxidation temperatures lower and higher than 700 °C, respectively.
|Uncontrolled Keywords:||Porous silicon - Thermal oxidation - Kinetic analysis - Structural transition - Optical properties|
|Subjects:||Physical Science > Nanophysics|
Material Science > Functional and hybrid materials
Material Science > Nanostructured materials
|Deposited On:||14 May 2010 14:58|
|Last Modified:||14 May 2010 14:58|
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