| 摘要 |
PROBLEM TO BE SOLVED: To provide a thin-film solar cell which has high conversion efficiency, even when a light-absorbing layer is made thin by providing constitution of a solar battery which suppresses extinction of carriers and reduction of a light absorption quantity due to recoupling at a reverse electrode accompanying the thickness reduction of the light-absorbing layer. SOLUTION: As a semiconductor thin film 3 of <=1 μm in film thickness which consists of group-I, group-III, and group-VI elements for forming a light- absorbing layer using In and Ga as group-III elements, a semiconductor thin film is used which has a distribution, varying in the relative value of the composition ratio of In and Ga along the film thickness. In particular, a constitution using a semiconductor thin film having a distribution decreasing in the composition ratio of Ga occupying the group-III elements from the side of an electrode film 2 to the side of window layers 4 and 5 is effective. Consequently, extinction of carriers due to recoupling on the reverse surface is suppressed and decrease in the efficiency of a solar battery due to thickness reduction of the light- absorbing layer 3 can be prevented. |
