Substrates for High-Efficiency Thin-Film Solar Cells Based on Crystalline Templates

A method for fabrication of a three-dimensional thin-film silicon substrate, the method comprising:

• forming a porous silicon layer on a silicon template having a top surface aligned along a (100) crystallographic orientation plane of the silicon template and a plurality of walls each aligned along a (111) crystallographic orientation plane of the silicon template wherein said walls form an inverted pyramidal cavity, said porous silicon layer formed substantially conformal to said silicon template;
• forming an epitaxial silicon layer on said porous silicon layer, wherein said epitaxial silicon layer is formed substantially conformal to said porous silicon layer;
• and
• releasing said epitaxial silicon layer from said silicon template.

A three-dimensional thin-film silicon substrate comprising a plurality of ridges on the surface of the silicon substrate defining a base opening of an inverted pyramidal cavity and a plurality of walls defining said inverted pyramidal cavity and wherein said silicon substrate was created according to a process comprising the steps of:

• forming a porous silicon layer on a silicon template having a top surface aligned along a (100) crystallographic orientation plane of said silicon template and a plurality of walls each aligned along a (111) crystallographic orientation plane of said silicon template wherein said walls form an inverted pyramidal cavity, said porous silicon layer formed substantially conformal to said silicon template;
• forming an epitaxial silicon layer on said porous silicon layer, wherein said epitaxial silicon layer is formed substantially conformal to said porous silicon layer;
• and
• releasing said epitaxial silicon layer from said silicon template.