| 摘要 |
PURPOSE:To reduce reflection loss by causing light irradiated onto the surface of a substrate to repeat its reflections a plurality of times in recessed parts and improve light receiving efficiency by installing a thin film semiconductor layer that generate a photovoltage on the surface of the substrate where a plurality of recessed parts are formed. CONSTITUTION:A P-I-N type thin film semiconductor layer 13 that generates a photovoltage is provided on the surface of a substrate 11 including inside faces of a plurality of recessed parts 12 formed at the surface of the electrode substrate 11 and then an electrode layer 14 is provided on the above semiconductor layer. If a bottom face of the recessed part 12 has an inclination of the angle theta to the other side face 12b, an incident light I incoming vertically to the recessed part 12 reflects to a side face 12c that is on the opposite side of 12b and furthermore, it reflects to the side face 12b to repeat reflections inside of the recessed part. Yet, the more times it reflects, the less it has reflection loss. When an interval between side faces 12b and 12c of the recessed parts 12 is represented with W and a reflection pitch to repeat a multipath reflection is represented with L, the following expression: L=2W tan (270 deg.-2theta) is valid and in the case of repeating three times of reflections, its expression is L=3W tan (270 deg.-2theta). When the bottom face 12a of the recessed part 12 is required to be tilted to allow the incident light to repeat the reflections, it is necessary for its angle theta of inclination to be within a range; that is 45 deg.<=theta<=135 deg.. |
