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

We reported the titanium dioxide (TiO2) 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 TiO2 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 TiO2 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 × 105 was achieved from the device with the electrode spacing of 30 μm. 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.