Fabrication and optimization of the thermally treated titanium dioxide thin film-based ultraviolet photodetectors

Abstract We reported the titanium dioxide (TiO ₂ ) thin film-based metal-semiconductor-metal (MSM) ultraviolet (UV) photodetectors (PDs), fabricated by conventional photolithography and electron-beam evaporation processes, with additional annealing. The crystallinity and morphology of the thermally treated TiO ₂ layers were investigated. In order to optimize the performance of MSM UV PDs, the annealing temperature ( T _a ) and electrode spacing were adjusted. The qualified anatase TiO ₂ thin films without structural deformation were obtained at the T _a of 600 °C. At the bias of 5 V, the high on/off ratio of 6.0 × 10 ⁵ was achieved from the device with the electrode spacing of 30 μ m. By switching the light on/off, the device operation was also observed. The average rise and reset times were estimated to be 34.2 and 5.5 s, respectively.