| 摘要 |
PURPOSE:To prevent reflection loss to enable light to reach the lowest layer for higher optical efficiency by a method wherein the refractive indeces of semiconductor layers are so set that they are higher as the distance from the side of incidence of light increases. CONSTITUTION:Refractive indeces are set at 3.8 for an n-type a-Si:H layer 5, 4.0 for a p-type muC-SiGe:H layer 4a, and 4.2 for an i-type a-SiGe:H layer 3, gradually higher as the distance from the side of incidence of light increases. With the layers being designed as such, a light beam landing on a side provided with a transparent conductive film 8 is not reflected by semiconductor layers but are absorbed by them, which allows the beam to arrive at the lowest layer. This eliminates optical loss, realizing an enhanced efficiency. |
