We have investigated the fabrication process of an alternative approach for a direct integration of epitaxial structures onto a foreign substrate. Our approach is based on the synthesis of a nanocomposite made of graphene-like carbon and porous silicon (GPSi). The nanocomposite was produced by anodization etching of a silicon substrate, followed by a thermal carbonization step. The main study focused on the preparation of the nanocomposite surface for subsequent epitaxial deposition. While the nanocomposite must retain its carbon content for thermal stability at epitaxial temperatures, the surface must be stripped of its residual carbon to expose the silicon crystal and support the layer nucleation. Our results show that the porous silicon (PSi) substrate, carbonized at 750 • C and subjected to an O 2 plasma treatment of 20W during 12s, presented a carbon-free surface, while the bulk porous structure retained its carbon coating. Subsequent growth of a crystalline GaAs thin film demonstrated the substrate ability to support epitaxy.