Patent ID: 8853521

Claim:
A method for making a see-through three-dimensional monocrystalline silicon thin film solar cell substrate, comprising the steps of: patterning a reusable monocrystalline silicon template; forming a sacrificial porous silicon release layer on a surface of said reusable monocrystalline silicon template; depositing a doped monocrystalline silicon film onto said sacrificial porous silicon release layer, said doped monocrystalline silicon film being substantially conformal to said sacrificial porous silicon release layer and having a thickness in the range of 2 to 50 microns for forming a three-dimensional monocrystalline silicon thin film solar cell substrate and having a three-dimensional topography corresponding to said patterned reusable monocrystalline silicon template and comprising: a plurality of discrete and isolated inverted pyramidal cavities at predetermined locations on said three-dimensional monocrystalline silicon thin-film solar cell substrate each comprising a pyramidal tip and tapered sidewalls, said plurality of discrete and isolated inverted pyramidal cavities having a pyramidal cavity height in the range of approximately 100 to 400 microns on a front surface of said three-dimensional monocrystalline silicon thin-film solar cell substrate, said plurality of discrete and isolated inverted pyramidal cavities having central axes substantially perpendicular to said front surface of said three-dimensional monocrystalline silicon thin-film solar cell substrate and having a ratio between height and side dimensions ranging from approximately 1.5 to 3; and a plurality of interconnected continuous ridges interspersed among and bordering said plurality of discrete and isolated inverted pyramidal cavities and associated to construct said monocrystalline silicon thin-film solar cell substrate as a free-standing, self-supporting substrate, and further having a ridge width ranging from approximately 0.5 to 5 microns on said front surface of said three-dimensional monocrystalline silicon thin-film solar cell substrate, wherein said three-dimensional monocrystalline silicon thin-film solar cell substrate, said plurality of discrete and isolated inverted pyramidal cavities, and said plurality of interconnected continuous ridges cooperate to enable a free-standing, self-supporting three-dimensional monocrystalline silicon thin-film solar cell with sufficient mechanical rigidity and resilience for reduced cell breakage rate in a solar cell production factory; detaching said three-dimensional monocrystalline silicon thin-film solar cell substrate from said reusable monocrystalline silicon template through separation at said sacrificial porous silicon release layer; and selectively removing a predetermined portion of a plurality of said pyramidal tips from said plurality of discrete and isolated inverted pyramidal cavities to create a plurality of see-through holes of specified opening area.