Patent ID: 8143514

Claim:
A method for fabricating a photovoltaic material comprising: providing a semiconductor substrate; forming a first layer and a second layer of porous semiconductor crystalline material on the semiconductor substrate, both layers comprised of a plurality of wormhole structures wherein density distribution of the wormhole structures in the first layer ranges from 10 10 /cm 3 to 10 20 /cm 3 and density distribution of the wormhole structures in the second layer ranges from 10/cm 3 to 10 10 /cm 3 , wherein the first layer is in between the second layer and the semiconductor substrate; forming a joining layer over a surface region of the second layer of the porous semiconductor crystalline material; joining the surface region of the second layer of the porous semiconductor crystalline material to a support; delaminating a portion of the porous semiconductor crystalline material from the semiconductor substrate while the second layer of the porous semiconductor crystalline material remains joined to the support via the joining layer, the delaminated portion of the porous semiconductor crystalline material forming a continuous layer of porous semiconductor crystalline material on the support, the delaminating creating a new surface of the porous semiconductor crystalline material, the new surface forming a light-incident surface of the photovoltaic material, the new surface having a texture configured to capture light incident on the surface of the photovoltaic material and characterized by cleaved wormhole structures and having a surface roughness of greater than about 10 nanometers to cause less than about 25% reflection from a total amount of irradiating incident light in a wavelength ranging from about 0.1 micron to about 5 microns; forming a substantially transparent incident light-trapping cover layer having a cover refractive index over the new surface, the cover layer having plural facets including wedge angles between adjacent facets configured to reflect incident light reflected from the new surface back into the new surface.