Control of valence band offset at CdS/Cu(In,Ga)Se2interface by inserting wide-bandgap materials for suppression of interfacial recombination in Cu(In,Ga)Se2solar cells

• DOI: 10.7567/jjap.54.08kc08
• Publication Date: 2015-07-09T08:13:17Z
• Authors: Takahito Nishimura; Yoshiaki Hirai; Yasuyoshi Kurokawa; Akira Yamada
• Keywords: Band offset; Open-circuit voltage

We inserted Cu(In,Ga)3Se5 into the CdS/Cu(In,Ga)Se2 interface of Cu(In,Ga)Se2 solar cells with a flat band profile and energy bandgaps (Eg) 1.2 1.4 eV in order to investigate repelling holes by effect valence offset (ΔEv). found that open circuit voltage (VOC) was clearly improved from 0.66 0.75 V Eg eV, although VOC only increased 0.63 0.64 eV. For high efficiency, we fabricated single-graded an average Eventually, conversion efficiency 14.4% obtained when thickness 30 nm inserted, 10.5% without Cu(In,Ga)3Se5. These results suggest importance ΔEv suppression interfacial recombination possibility highest could be achieved.