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Oxygen Absorption in Free-Standing Porous Silicon: A Structural, Optical and Kinetic Analysis

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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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.

Item Type:Article
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
ID Code:8838
Deposited By:IoN
Deposited On:14 May 2010 14:58
Last Modified:14 May 2010 14:58

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