Nanostructured iron(III) oxide deposits are grown by chemical vapor deposition (CVD) at 400−500 °C on Si(100) substrates from
Fe(hfa)2TMEDA (hfa = 1,1,1,5,5,5-hexafluoro-2,4-pentanedionate; TMEDA =
N,N,N′N′-tetramethylethylenediamine), yielding the selective formation of α-Fe2O3or the scarcely studiedε-Fe2O3 polymorphs under suitably optimized preparative conditions. By using Ti(OPr
i)4(OPri= iso-propoxy) and water asatomic layer deposition (ALD) precursors, we subsequently functionalized
the obtained materials at moderate temperatures (<300°C) by an ultrathin
titanomagnetite (Fe3−xTixO4) overlayer. An extensive multitechnique character-ization, aimed at elucidating the system structure, morphology, composition and
optical properties, evidenced that the photoactivated hydrophilic and photocatalytic behavior of the synthesized materials is dependent both on iron oxide phase composition and ALD surface modification. The proposed CVD/ALD hybrid synthetic approach candidates itself as a powerful tool for a variety of applications where semiconductor-based nanoarchitectures can benefit from the coupling with an ad hoc surface layer.