Eur. Phys. J. B 16, 447-454 (2000)
https://doi.org/10.1007/s100510070202

In situ X-ray diffraction investigation of porous silicon strains induced by the freezing of a confined organic fluid

Laboratoire de Spectrométrie Physique, Université J. Fourier (Grenoble-I) (CNRS UMR 5588) , BP 87, 38402 St Martin d'Hères Cedex, France

Corresponding author: ^a Gerard.Dolino@ujf-grenoble.fr

Received: 22 October 1999
Revised: 25 March 2000
Published online: 15 August 2000

Abstract

High resolution X-ray diffraction is used to perform an in situ measurement of the variations of the lattice parameter of the nanometer size crystallites of porous silicon, induced by the freezing of a confined organic fluid, dodecane. Two p⁺ type PS layers of 60 and 70% porosity are investigated, and the variations of their lattice parameter with the temperature (in the range 150-300 K) are measured. The experimental curves are discussed in relation with the results of a previous calorimetric study of the freezing of confined dodecane. We explain the observed strains by the presence of capillary stresses, that appear in the layer due to the formation of internal liquid-vapour meniscus during the freezing process of the confined fluid.