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

摘要

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=I-on/I-off) of bare BTO based photodetector was found to be 8.36 x 10(2) for UV radiation (lambda = 365 nm and intensity = 24 mu W/cm(2)). The modifier, tungsten (W) in the form of both thin overlayer and uniformly distributed circular dotted structures (600 mu m 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 x 10(4)) 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 (I-off) due to formation of schottky junction between the oxide (BTO) and metal (W), and (2) enhancement in photocurrent (I-on) due to high absorption of UV radiation on the detector surface. (C) 2015 Elsevier B.V. All rights reserved.