[19p-W541-1~14] Efficiency improvement for thin film compound semiconductor solar cells in the present and future

△ [19p-W541-6] Improvement of efficiency of Cu(In,Ga)S₂ thin-film solar cells by Zn_1-xMg_xO buffer layer

〇HOMARE HIROI^1,2,3, Yasuaki Iwata^1,2, Hiroki Sugimoto^1,2, Akira Yamada³ (1.Solar Frontier, 2.Showa Shell Sekiyu, 3.Tokyo Tech.)

Keywords:thin-film solar cells,chalcogenide solar cells,Se-free Cu(In,Ga)S2

Se-free Cu(In,Ga)S₂ is a promising material for solar cells from an aspect of low-cost production because H₂Se which is an expensive material can be removable. However, there is no remarkable progress in the field of Se-free Cu(In,Ga)S₂ solar cells these days. Additionally, Se-free Cu(In,Ga)S₂ solar cells have further two difficulties in mass-production. The one is KCN-etching process for absorbers and the other is CdS deposition for buffer layers. Based on these backgrounds, we tried fabricating Se-free Cu(In,Ga)S₂ solar cells via KCN-free and Cd-free processes. As a result, the high performances were achieved on Se-free Cu(In,Ga)S₂ solar cells. In this paper, we focused on the Cd-free buffer layer by using Zn_1-xMg_xO, and revealed the dependence of electrical parameters on Mg content of Zn_1-xMg_xO buffer layer for Se-free Cu(In,Ga)S₂ solar cells. Furthermore, the latest result of our research on Se-free Cu(In,Ga)S₂ solar cells will be shown at the conference.