Tailoring of Optoelectronic Properties of ϵ‐Fe2O3 Thin Films Through Insertion of Organic Interlayers

Combined atomic/molecular layer deposition (ALD/MLD) technique enables the engineering of inorganic–organic superlattices with atomic/molecular layer accuracy for the individual layer thicknesses. Here we demonstrate how the optical and electronic properties of ϵ‐Fe2O3 thin films can be gradually tuned with an insertion of monomolecular organic layers. In our ϵ‐Fe2O3:benzene superlattice (SL) structures the thickness of individual iron oxide layers varies in the range of 1–17 nm. With decreasing ϵ‐Fe2O3 layer thickness, that is, SL period, the films become more transparent. Moreover revealed from the UV–vis spectra is that the indirect optical bandgap increases from ≈2.0 eV for ϵ‐Fe2O3 up to ≈2.3 eV for the SL films with the shortest SL period. We foresee that the ALD/MLD approach presented here for the ϵ‐Fe2O3–benzene thin films can be exploited in fabricating many other interesting hybrid material systems with controlled optoelectronic properties. This Letter reports the possibility to tailor the optoelectronic properties of ϵ‐Fe2O3 thin films through insertion of monomolecular organic interlayers. This is achieved by using the combined atomic/molecular layer deposition (ALD/MLD) technique which enables the engineering of inorganic–organic superlattices with atomic/molecular layer accuracy for the individual layer thicknesses.