Progress in large-area CIGS-based modules with sputtered-GZO window

An objective of this study is to reduce the efficiency gap of 30 cm× 30 cm-sized CIGS-based thin-film modules with MOCVD-ZnO:B or sputtered-5.7GZO (ZnO:5.7wt%Ga) window. Based upon a growth model of MOCVD-ZnO:B window, a thin intrinsic-ZnO layer with the thickness of 50 nm is prepared on a CBD-Zn(O,S,OH)_x buffer by RIF sputtering in the case of sputtered-5.7GZO window. This approach contributes to maintain the reproducibility of our current baseline process and leads to the achievement of the module efficiency of 12.2 % with this window, which has been measured by NREL. It is emphasized that 1) this gap is reduced up to 1 % by making a module, and 2) low-cost packaging technologies without any J_sc loss and suitable to CIGS-based thin-film circuits should be developed promptly.