Synthesis and characterization of titanium-alloyed hematite thin films for photoelectrochemical water splitting

We have synthesized pure and Ti-alloyed hematite thin films on F doped SnO2 coated glass substrates by radio frequency magnetron co-sputtering of iron oxide and titanium targets in mixed Ar/O2 and mixed N2/O2 ambient. We found that the hematite films deposited in the N2/O2 ambient exhibit much poorer crystallinity than the films deposited in the Ar/O2 ambient. We determined that Ti alloying leads to increased electron carrier concentration and crystallinity, and reduced bandgaps. Moreover, Ti-alloyed hematite thin films exhibited improved photoelectrochemical performance as compared with the pure hematite films: The photocurrents were enhanced and the photocurrent onset shifted to less positive potentials.