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In this letter, TiO2 thin films were prepared via sol-gel method and metal/semiconductor/metal ultraviolet (UV) detectors with Pt Schottky contact were fabricated. At 5 V bias, the dark current of the device was only 80 pA. Diffusion theory was adopted to analyze the low dark current mechanism, which is consistent with the experimental results. The device shows a remarkably reduced decay time of 41.53 ms. The low dark current and improved time response performance may be attributed to the high effective Schottky barrier between Pt and TiO2 film. High responsivity of 34.5 A/W was achieved at 300 nm UV light and the ratio of photocurrent to dark current is about five orders of magnitude, which is much larger than that of other semiconductor photodetectors.

In this letter, metal–semiconductor–metal (MSM) ultraviolet TiO 2 photodetectors based on LaAlO 3 substrate were fabricated. TiO 2 nano-film was prepared via a sol–gel method, and then was spin-coated on single crystal LaAlO 3 substrate. Pt interdigitated electrodes were deposited on the top of TiO 2 film. At 5 V bias, the dark current of the detector was only 50 pA, which is much lower than TiO 2 -based detector. When irradiated by 270 nm UV light, a high photoresponse of the device was obtained. The ratio of photocurrent to dark current was nearly 5 orders, which is much higher than other photodetectors based on TiO 2 reported. The rise and fall time of the detector were 550 ms and 380 ms, respectively. The very low dark current and high sensitivity demonstrate the excellent application of the device in UV photoelectric detection.

In this letter, a nanocrystalline SrZr0.1Ti0.9 O3thin film was synthesized by sol-gel method and characterized by means of X-ray diffraction, X-ray photoelectron spectroscopy, atomic force microscopy, and UV-visible absorption spectra. Interdigitated Au electrodes were deposited on the film to fabricate metal-semiconductor-metal ultraviolet photodetector. At 5-V bias, the dark current of the device was 41 pA. Under the irradiation of 260-nm UV light, peak responsivity of 94 mA/W was achieved, which was higher than that of pure SrTiO3-based photodetectors. The higher responsivity of the SrZr0.1Ti0.9O3 device may be due to the introduction of zirconia, which would induce more oxygen vacancies. The UV/visible rejection ratio R260 nm/R380 nm was more than three orders of magnitude, indicating excellent sensitivity. The rise time and fall time of the device were 3.8 and 565 ms, respectively.

In this letter, TiO2 nanocrystalline film was prepared on SrTiO3 (001) substrate to form an n-n heterojunction active layer. Interdigitated Au electrodes were deposited on the top of TiO2 film to fabricate modified HMSM (heterojunction metal-semiconductor-metal) ultraviolet photodetector. At 10 V bias, the dark current of the detector was only 0.2 nA and the responsivity was 46.1 A/W at 260 nm. The rise and fall times of the device were 3.5 ms and 1.4 s, respectively. The TiO2/SrTiO3 heterojunction contributed a lot to the high responsivity and reduced the fall time, which improved the device performance effectively. These results demonstrate the excellent application of TiO2/SrTiO3 heterojunction in fabricating high performance UV photodetectors.