| 摘要 |
PROBLEM TO BE SOLVED: To increase optical absorption of a semiconductor layer and provide a photovoltaic element having excellent workability and reliability, by using an opaque substrate having line-shaped recess and protrusion. SOLUTION: A photovoltaic element is constituted of a substrate 101, a back side metal reflective layer 102, a transparent conductive layer 103, an n-type semiconductor layer 104, an i-type semiconductor layer 105, a p-type semiconductor layer 106, a transparent electrode 107 and a collector electrode 108. It is preferred that the surface shape of the substrate has line-shaped recess and protrusion. In the case where the recess and protrusion are linearly formed, it is preferred that Ra(X) is 15-300nm, 20-200nm, 25-150nm while Ra(Y) is 20-600nm, 40-400nm, 60-300nm, where Ra(X) represents the centerline average roughness at the time of scanning in parallel to the lineshaped recess and protrusion while Ra(Y) represents the centerline average roughness at the time of perpendicular scanning. In addition, Ra(X)/Ra(Y) is preferably 0.8 or less, more preferably 0.6 or less, and optimally 0.4 or less. |
