| 摘要 |
The present invention relates to an optical absorption layer of a kesterite (Cu2ZnSnSe4) material of a solar battery by a spatial energy band gap modulation method, and a method for making a conduction band having a slope in a kesterite optical absorption layer. An optical absorption layer consisting of three layers of Cu2Zn(GexSn1-x)Se4 where Sn is partially substituted with Ge is made. If Sn is substituted with Ge, the energy band gap of the material is increased. The optical absorption layer is divided into three layers, and an amount of substituted Ge in an upper layer and a lower layer is larger than an amount of substituted Ge in a middle layer. If the upper layer and the lower layer of the optical absorption layer are compared, more Ge is substituted in the lower layer to increase the energy band gap. Photo-excited electrons are easily collected towards a transparent electrode positioned above the upper layer of the optical absorption layer, and a photocurrent is increased in the optical absorption layer. |
