Monocrystalline Si waffles for thin solar cells fabricated by the novel perforated-silicon process

We apply the novel perforated-silicon process ("psi-process") for the fabrication of thin (a few microns thick) monocrystalline silicon layers for solar cells with textured surfaces for efficient light trapping. A silicon layer grows epitaxially on the porous surface of a textured monocrystalline Si substrate. Mechanical stress splits the porous layer and thereby separates the epitaxial layer from the substrate. X-ray diffraction analysis proves monocrystallinity for our 5.8-mu m-thick Si layer. Ray tracing simulations correctly model the optical reflectance measurements. The simulations predict a maximum short-circuit current of 36.5 mA/cm(2) for this waffle-shaped film when it is attached to glass substrates.