NOVELTY - The solar cell comprises a first conductor (62), a doped thin-film silicon layer (68) in electrical communication with the first conductor, a doped amorphous diamond layer (64) in contact with the doped thin-film silicon layer, a transparent second conductor (70) in electrical communication with the doped amorphous diamond layer, a substrate disposed under the first conductor and the second conductor, and junctions. The doped amorphous diamond layer has a thickness of less than 250 nanometers. The doped thin-film silicon layer is a P-type material.    USE - Used as a solar cell.    ADVANTAGE - The solar cell can be easily and economically manufactured with high conversion efficiency and without the need for single crystal semiconductor substrates, and reduces the back conversion of excited electrons to heat using a layer of amorphous diamond.    DETAILED DESCRIPTION - The solar cell comprises a first conductor (62), a doped thin-film silicon layer (68) in electrical communication with the first conductor, a doped amorphous diamond layer (64) in contact with the doped thin-film silicon layer, a transparent second conductor (70) in electrical communication with the doped amorphous diamond layer, a substrate disposed under the first conductor and the second conductor, and junctions. The doped amorphous diamond layer has a thickness of less than 250 nanometers. The doped thin-film silicon layer is a P-type material, and the doped amorphous diamond layer is an N-type material. The substrate is a polymer material, and pliable to enable the solar cell to be affixed to a curved surface. The second conductor comprises a doped portion of the amorphous diamond layer, and a carbon nanotube layer comprising a non-planar surface. The amorphous diamond layer and the thin-film silicon layer conform to the non-planar surface of the carbon nanotube layer to form a non-planar junction. A light absorbing layer is disposed between the second conductor and the amorphous diamond layer. Each junction comprises the first conductor, a doped thin-film silicon layer in contact with the first conductor, and a doped amorphous diamond layer in contact with the doped thin-film silicon layer. The amorphous diamond layer has a thickness of less than 250 nanometer. Two of the junctions have an equal or different band gap. A dielectric layer is interposed between the doped thin-film silicon layer and the doped amorphous diamond layer. INDEPENDENT CLAIMS are included for:    (1) a method of reducing back conversion of excited electrons into heat in an amorphous diamond layer; and    (2) a method of making a solar cell.    DESCRIPTION OF DRAWING(S) - The figure shows a cross-sectional view of a solar cell.    First conductor (62)    Amorphous diamond layer (64)    Interface layer (66)    Thin-film silicon layer (68)    Second conductor (70)    Light absorbing layer. (72)