Fig. 4

Cross-sectional imaging and chemical mapping of Zn/Sn-doped p-n pseudocubic Fe₂O₃ photoelectrode: a–f STEM images of the cross-section of an Zn/Sn-doped PN pseudocubic Fe₂O₃ photoelectrode. Note that the thin Pt layer seen in the image was deposited over the sample as a protection layer for the focused ion beam (FIB) milling step for cross-sectional sample preparation. g EDS mapping showing Zn, Fe, Sn, and Si elemental distributions respectively for the same sample as in a