  Ferric oxide (Fe2O3) thin films were fabricated on amorphous nonconductive
and FTO conductive glass substrates starting from iron acetate nanoparticles by
the doctor blade and the spin coating techniques. Thin films of Fe2O3 with and
without the PEG binder were investigated. Films were subsequently annealed at
500 0C in air for 1 hour to crystallize the phase Fe2O3. The structural and
chemical properties of Fe2O3 thin films were determined using XRD and FTIR.
According to XRD, the single phase of Fe2O3 crystallized in the thin film after
annealing. The optical band gap of synthesized Fe2O3 thin films were determined
by UV-Visible spectrums. Gas sensitivity, respond time and recovery time of
Fe2O3 thin films were measured in 1000ppm of CO2 gas using AUTO LAB. Thin films
synthesized by the doctor blade method were thicker and more uniform than the
thin films prepared by the spin coating technique. Gas sensitivity of Fe2O3
films synthesized by the doctor blade method is slightly higher than that of
the films fabricated by the spin coating technique. Fe2O3 films with the PEG
binder posses a higher gas sensitivity, lower respond time and lower recovery
time compared to films without PEG binder. After adding the PEG binder, the
optical band gap of Fe2O3 thin films reduces. The reduction of the activation
energy is the reason for the improvement of the gas sensitivity after adding
the PEG. However, the peak positions of FTIR do not indicate any significant
change due to the adding of the PEG. Adding the binder increased the gas
sensitivity of iron oxide by 15.44%. Both FTIR and UV-Visible data confirm the
formation of Fe2O3 in the thin film.
