Growth and fabrication of sputtered TiO2 based ultraviolet detectors

TiO2 films with high crystallinity and good stoichiometry were prepared by magnetron sputtering technique under the optimized process conditions and analyzed by various characterization methods. Metal-semiconductor-metal (MSM) structure detectors with diverse finger spacings were then fabricated on the TiO2 films by employing Au as the Schottky contact metal. Low dark current, large UV responsivity, and high UV-to-visible rejection ratio (310 versus 400 nm) were found in these detectors. In particular, the lowest dark current of 4.58 nA/cm2 at 5 V bias and the highest UV-to-visible rejection ratio of 3.52 × 103 were achieved in the detectors with 10 μm finger spacing which are comparable to the best results in the TiO2 based detectors reported to date. Considering the simple fabrication process and low cost, the sputtered TiO2 based MSM detectors are very promising in commercial production for the UV detection applications.