Ultraviolet radiation detection by barium titanate thin films grown by sol–gel hydrothermal method

• Ultraviolet photodetector prepared using ferroelectric barium titanate thin film.
• The photoconductive gain of bare BTO based photodetector was found to be 8.36 × 102.
• W(dots)/BTO photodetector showed enhanced photoresponse by two orders.
• Schottky junction formation enhances photoresponse for W(dots)/BTO photodetector.

Ultraviolet (UV) photodetector using ferroelectric barium titanate, BaTiO3 thin film has been prepared successfully. BaTiO3 (BTO) this film is deposited by sol–gel hydrothermal (SG-HT) method. The deposited BTO films were found to be polycrystalline having a band gap of about 3.51 eV. The photoconductive gain (K = Ion/Ioff) of bare BTO based photodetector was found to be 8.36 × 102 for UV radiation (λ = 365 nm and intensity = 24 μW/cm2). The modifier, tungsten (W) in the form of both thin overlayer and uniformly distributed circular dotted structures (600 μm diameter) were integrated with the surface of BTO thin film by rf-magnetron sputtering technique to improve the photoresponse characteristics. The photoconductive gain was enhanced to about two orders of magnitude (1.84 × 104) after integration of W modifier in the form of circular dots. The significant enhancement in photoresponse for W(dots)/BTO photodetector is related to the twin effect of (1) reduction in dark current (Ioff) due to formation of schottky junction between the oxide (BTO) and metal (W), and (2) enhancement in photocurrent (Ion) due to high absorption of UV radiation on the detector surface.