Dresden 2017 – wissenschaftliches Programm
HL 4.2: Topical Talk
Montag, 20. März 2017, 10:00–10:30, CHE 89
Impact of growth condition on defect generation in Cu(In,Ga)Se2 — •Takeaki Sakurai1, Muhammad Islam1, Akira Uedono1, Shogo Ishizuka2, Hajime Shibata2, Shigeru Niki2, and Katsuhiro Akimoto1 — 1University of Tsukuba, Tsukuba, Japan — 2National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
Characterization of defects in Cu(In,Ga)Se2 (CIGS)-based solar cells is an important research subject for understanding its carrier recombination processes. In this decade, the optical and electrical response of the defect states have been intensely studied using various analytical methods. Nevertheless, the origin and distribution of the defects in CIGS have not been fully understood yet due to its complex device structures and multinary compositions. During the growth of CIGS, in particular, segregation of the secondary phase, selenization, and alkali metal diffusion occur, and the difficulty in the control of the growth process mainly results in fluctuation of their optoelectronic properties. Therefore, a systematic study on the relation between the thin film growth and the generation of defects is necessary. In this study, we have investigated the impact of growth condition (Se flux and Ga concentration) on defect generation in CIGS by using various characterization techniques. We want to point out that the defect level centered around 0.8 eV from the valence level may act as a recombination center at room temparature. We will discuss whether this defect level acts as a recombination ceneter by using two-wavelength excited photoluminescence method.