Evaluation of electronic transport and optical response of two-dimensional Fe-doped TiO2 thin films for photodetector applications

We have carried out the structural, electronic and optical properties of Iron (Fe)-doped TiO2 thin films by sol-gel technique. The results reveal that the thin films form in a granular structure where particle-like grains cover the surface. Photophysical features of the thin films are performed by UV-vis spectrometry. The optical bandgap of undoped TiO2 thin film decreases from 3.17 eV to 3.05 eV with an increase in atomic ratios of Fe content, so the electron transfer is easier from the valence band to the conduction band. The current-voltage (I-V) and capacitancevoltage (C-V) characteristics of the undoped and Fe-doped TiO2 thin films are investigated under dark and various lighting intensities. Our results show that the photocurrents increase with increasing intensities of illumination. The photodiodes also show a decreasing capacitance with increasing frequency. From I-V and C-V plots, the photodiodes show rectifying properties and good photovoltaic behavior. Herein, the results display that the produced new Fe-doped TiO2 thin film samples can be used for photodetector applications.