Thin film solar cell
Optimal structures for high efficiency thin film silicon solar energy conversion devices and systems are disclosed. Thin film silicon active layer photoelectron conversion structures using ion implantation are disclosed. Thin film semiconductor devices optimized for exploiting the high energy and ultraviolet portion of the solar spectrum at the earths surface are also disclosed. Solar cell fabrication using high oxygen concentration single crystal silicon substrates formed using in preference the CZ method are used advantageously. Furthermore, the present invention discloses optical coatings for advantageous coupling of solar radiation into thin film solar cell devices via the use of rare-earth metal oxide (REO x ), rare-earth metal oxynitride (REO x N y ) and rare-earth metal oxy-phosphide (REO x P y ) glasses and or crystalline material. The rare-earth metal is chosen from the group commonly known in the periodic table of elements as the lanthanide series.
1. A device for converting radiation to electrical energy comprising:
a substrate;
a layer of a large band gap material wherein the large band gap material has a band gap of at least 1.2 eV and consists of at least one rare-earth ion and at least one of oxygen, phosphorus and nitrogen; and
a layer of a small band gap material for converting radiation to electrical energy, such that the layer of the large band gap material is contacting the layer of the small band gap material.
2. The device of claim 1 wherein said small band gap material comprises at least one from a group comprising Group IV, III-V, and II-VI semiconductors and combinations thereof.
3. The device of claim 1 wherein said large band gap material is single crystal.
4. The device of claim 1 wherein said substrate transmits a majority of said radiation impinging upon it to the large band gap material.
5. A device for converting radiation to electrical energy comprising:
a substrate;
a layer of a large band gap material; and
a layer of a small band gap material for converting radiation to electrical energy, such that the layer of the large band gap material is contacting the layer of the small band gap material; and
the large band gap material is chosen from a group consisting of rare-earth oxide (RE x O z ), rare-earth-oxide-phosphide (RE x O z P w ), rare-earth-oxide-nitride (RE x O z N w ), rare-earth-oxide-nitride-phosphide (RE x O z N w P q ) and combinations thereof.