Formation and characterization of crystalline iron oxide films on self-assembled organic monolayers and their in situ patterning

Crystalline and pore-free films of α-Fe₂O₃ were prepared on hydrophilic self-assembled organic monolayers (DTT-SAMs) at 80 °C. Subsequently, Fe₃O₄ and γ-Fe₂O₃ films were synthesized via post annealing of as-deposited α-Fe₂O₃. In situ patterning of crystalline iron oxide thin layers was achieved via microcontact printing (μCP) and selective deposition.μCP was used to pattern two different surface moieties of self-assembled organic monolayers (SAMs) on Au-Cr-Si substrates. An elastomeric stamp was used to transfer either hexadecanethiol (HDT) SAMs, which are to sustain deposition of iron oxide precipitates, or hydrophilic SAMs [e.g., dithiothreitol (DTT)]. Selective deposition was realized through precipitation of iron oxide phases. Iron oxide films were deposited onto hydrophilic SAMs, but not onto HDT surfaces. Line (width of <1 μm) patterns in crystalline α-Fe₂O₃ thin films were obtained.