NOVELTY - A thin film silicon solar energy conversion device (6706) comprises a substrate; at least one layer of a large band gap material; and at least one layer of a small band gap material for converting radiation to electrical energy, such that the layers of the large band gap material are contacting a layer of the small band gap material.    USE - For converting radiation to electrical energy, for electric, optoelectronic applications, and in hetero-junction bipolar phototransistors (HBPTs), majority carrier devices; and photoconductors.    ADVANTAGE - The thin film solar cell optimized for exploiting the high energy and ultraviolet portion of the solar spectrum at the earth surface. The thin film reduces the manufacturing cost via reducing the amount of high quality single crystal-silicon (sc-Si) consumed in solar cell and the use of cheaper substrates, such as glass, metal, polymer and or flexible substrates. That is, the bulk sc-Si substrate CZ manufacturing process produces the highest crystalline structure perfection and thus the highest efficiency solar cell. Sawing techniques are limited to sc-Si film thickness of the order of millimeters. The device exploits the use of oxygen containing CZ Si wafer for the direct application for the purpose thin film cleaving and separation method. The control of oxygen concentration in CZ Si is of paramount importance for application to complementary metal oxide semiconductor ultra-large-scale-integrated-circuits (CMOS ULSICs). The device is manufactured using cheaper CZ production method, and reduces energy loss mechanism.    DETAILED DESCRIPTION - A device/thin film solar cell (6706) for converting radiation to electrical energy comprises a substrate; at least one layer of a large band gap material; and at least one layer of a small band gap material for converting radiation to electrical energy, such that the layers of the large band gap material are contacting a layer of the small band gap material. The large band gap material has a band gap of at least 1.2 eV. The substrate transmits a majority of radiation impinging upon it to the layers of a large band gap material. The device comprises an active layer/region containing large band gap material layer and a small band gap material layer; and an optically transparent conducting oxide over at least a portion of the surface of the active layer. The optically transparent conducting oxide comprises at least one rare-earth ion. The active region contains at least one rare-earth metal ion, at least one elemental or compound semiconductor and at least one element chosen from oxygen, nitrogen, and phosphorus. The device has a replacement substrate with electrodes connecting to the active layer. The active layer contains at least one lateral p-n junction, at least two lateral p-n-p junctions, or at least one vertical p-i-n structure, and several p+ contacts to the active layer. The large band gap material is chosen from rare-earth oxide (RExOz), rare-earth germanium oxide (RExGeyOz), rare-earth silicon oxide (RExSiyOz), rare-earth-silicon-oxide-phosphide (RExSiyOzPw), rare-earth-silicon-oxide-nitride (RExSiyOzNw), and rare-earth-silicon-oxide-nitride-phosphide (RExSiyOzNwPq). An INDEPENDENT CLAIM is included for producing a thin film involving providing a first Czochralski (CZ) grown substrate having a first surface and comprising a predetermined level of a first reactant; introducing ions of a second reactant into the first surface, such that the ions are distributed about a predetermined fracture depth; bonding a second substrate to the first surface of the first substrate; and heating the first and second substrates to combine the first and second reactants.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of wavelength dependent photo-generated carrier regions within lateral graded field solar cell.    Short wavelength photons (6701)    Long wavelength photons (6702)    Anti-reflection coupler (6703)    Photo-generated carriers (6704, 6705)    Thin film solar cell. (6706)