Fig. 2: HAADF-STEM of Ta:Fe2O3 and Ta:Fe2O3@Fe2O3 homojunction.

a HRSTEM image of Ta:Fe2O3 nanorods (circles are Ta atoms). b SAED of Ta:Fe2O3. c–f EELS mapping for a Ta:Fe2O3@Fe2O3 homojunction nanorod. g HRSTEM of homojunction nanorod (inset is the corresponding EELS linear scanning along the dashed arrow in e. The scale bar is 40 nm in c–f and 2 nm in a and g.