Bandgap narrowing in the layered oxysulfide semiconductor Ba
3
Fe
2
O
5
Cu
2
S
2
: Role of FeO
2
layer
Zhang Han
1
, Jin Shifeng
1, †,
, Guo Liwei
1
, Shen Shijie
1
, Lin Zhiping
1
, Chen Xiaolong
1, 2
PXRD pattern collected from the Ba
3
Fe
2
O
5
Cu
2
S
2
sample and the Rietveld refinement profiles.