Improved separation efficiency of photogenerated carriers for Fe2O3/SrTiO3 heterojunction semiconductor

To investigate the mechanisms of the improvement on separation efficiency of photogenerated carriers , a Fe 2 O 3 /SrTiO 3 heterojunction semiconductor with an improved separation efficiency was successfully prepared. The heterojunction semiconductor was characterized with X-ray diffraction (XRD), UV–vis absorption spectrum , scanning electron microscope (SEM) and surface photovoltage (SPV) spectroscopy. The energy band diagrams of Fe 2 O 3 and SrTiO 3 were determined with X-ray photoelectron spectroscopy (XPS), based on which the conduction band offset (CBO) between Fe 2 O 3 and SrTiO 3 was quantified to be 1.26 ± 0.03 eV. The recombination of photogenerated carriers was investigated with photoluminescence (PL) spectrum, which indicates that the formation of Fe 2 O 3 /SrTiO 3 decreases the recombination. Thus the improved separation efficiency is mainly due to the energy difference between the conduction band edges of Fe 2 O 3 and SrTiO 3 , and the decreased electron-hole recombination for Fe 2 O 3 /SrTiO 3 .