Low-coherence interferometry measurement of filling in porous silicon

Abstract

The determination of capillary filling dynamics in nanoporous structures and, in particular, the analysis of the filling fraction profile in the advancing wet front have been proposed as possible methods for characterizing the pore distribution of these structures. Furthermore, the filling dynamics in nanoporous structures of known morphology allows studying fluid properties under conditions of strong spatial confinement. In this work we determine the capillary filling dynamics of porous silicon structures using low-coherence interferometry. When the liquid enters the porous structure there is an increase in the optical thickness of the layer. The determination of optical thickness as a function of position and time allows monitoring capillary filling dynamics. The high spatial resolution of this technique allows to analyze the wet front broadening, which can be used to obtain information about the pore distribution in the sample