Abstract

GUTIERREZ, A.; GIRALDO, J.  and  RODRIGUEZ-GARCIA, M.E.. Técnica fotoacústica aplicada a la determinación de propiedades térmicas de muestras de silicio poroso. Rev. mex. fis. [online]. 2011, vol.57, n.2, pp.99-105. ISSN 0035-001X.

The photoacoustic technique is a technique that studies the radiation-matter interaction through a well-known phenomenon as photoacoustic effect. In this work using a theoretical fitting of the photoacoustic signal amplitude the effective thermal effusivity of porous silicon samples was determined. The porous samples were obtained by means of photoelectrochemical etching of (100) n-type silicon wafers with different resistivity values, all in the range of 1 -25 Ω cm. The samples were formed at room temperature in an electrolytic bath composed by a mixture of hydrofluoric acid (48 %) and ethanol having a composition ratio of 1:1 in volume under potentiostatic condition (20 V) and an etching time of 2 minutes using back illumination provided by a laser beam with a wavelength of 808nm. The obtained values for the effective thermal effusivity of the porous samples diminished respect to the corresponding value of single-crystalline silicon, this decrease can be attributed to the restriction of the mean free path of phonons in the porous network.

Keywords : Porous silicon; photoacoustic; thermal properties.

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