Cu(In,Ga)Se₂ superstrate-type solar cells with Zn_{1?span style='font-style: italic'>x}Mg_xO buffer layers

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• 作者：Takashi Minemoto ; ^{minemoto@se.ritsumei.ac.jp} ; Shinya Harada ; Hideyuki Takakura
• 关键词：Solar cell ; Thin film ; Cu(In ; Ga)Se2 ; Buffer layer ; Conduction band offset
• 刊名：Current Applied Physics
• 出版年：2012
• 出版时间：January, 2012
• 年：2012
• 卷：12
• 期：1
• 页码：171-173
• 全文大小：284 K

文摘

Superstrate-type Cu(In,Ga)Se₂ (CIGS) thin film solar cells were fabricated using Zn_1?em>xMg_xO buffer layers. Due to the diffusion of Cd into CIGS during the growth of the CIGS layer, the conventional buffer material of CdS is not suitable. ZnO is a good candidate because of higher thermal tolerance but the conduction band offset (CBO) of ZnO/CIGS is not appropriate. In this study, the Zn_1?em>xMg_xO buffer layers were used to fulfill both the requirements. The superstrate-type solar cells with a soda-lime glass/In₂O₃:Sn/Zn_1?em>xMg_xO/CIGS/Au structure were fabricated with different band gap energies of the Zn_1?em>xMg_xO layer. The CIGS layers [Ga/(In?+?Ga)?.25] were deposited by co-evaporation method. The substrate temperature during the CIGS deposition of 450?¡ãC did not cause the intermixing of the Zn_1?em>xMg_xO and CIGS layers. The conversion efficiency of the cell with Zn_1?em>xMg_xO was higher than that with ZnO due to the improvement of open-circuit voltage and shunt resistance. The results well corresponded to the behavior of the adjustment of CBO, demonstrating that the usefulness of the Zn_1?em>xMg_xO layer for the CBO control in the superstrate-type CIGS solar cells.