| 摘要 |
PURPOSE:To obtain a solar cell having a high conversion efficiency by inserting a strain superlattice layer which laminates alternately a CdS layer and an n-type CdTe layer between a p-type CdTe layer and an n-type CdS layer. CONSTITUTION:A super lattice layer 2, which comprises an ntype CdS layer and an n-type CdTe layer, is adapted to grow on the surface of a p-type CdTe single crystal substrate. Ga is doped and turned into an n-type dovpant on the surface where CdS is arranged to grow so that an n-type CdS layer 3 may be obtained. A solar cell with this structure produces less lattice strain and less lattice defect compared with ones with other structures where a p-type CdTe layer 1 and an n-type CdS layer 3 are directly joined to each other. A p-n junction plane does not penetrate the CdTe layer 1 while the thickness of the light which passes from the n-type CdS side to the junction plane is small. Furthermore, the optical absorption of the superlattice film is also little and increases the light which can arrive at a CdTe substrate 1. This construction makes it possible to improve the conversion efficiency of solar cells. |
