We investigate the application of porous silicon (PS) in the field of the photovoltaic. In first step we realise a double porous silicon layer by electrochemical anodisation using two different current densities. The low current leads to a low porosity and during annealing, the recrystallisation of this layer allows epitaxial growth. The second current leads to a high porosity which permits the transfer onto a low cost substrate. During high temperature onto hydrogenation treatments of to passivate the structure and epitaxy in liquid phase, porous silicon is recristallized partially. In this work, a characterization by scanning electron microscopy informs us about the morphology of these porous layers.