Electrode effect on high-detectivity ultraviolet photodetectors based on perovskite oxides

Abstract

High-detectivity metal-semiconductor-metal ultraviolet photodetectors have been fabricated based on SrTiO3 with different types of metal electrodes (Ag, Ni, and Pt), and the effects of the different types of the electrodes on the photoelectric properties were investigated. Comparing with three types of the metal electrodes, the largest responsivity of 0.517 A/W and the smallest dark current of 2.215 × 10−11 A were obtained by using Ag electrode due to the largest Schottky barrier between Ag electrode and SrTiO3. The detectivities of all the photodetectors are achieved about 1012 cm·HZ1/2/W, which can be comparable to Si-based photodetectors. Furthermore, a transient photovoltaic signal with a rise time of ∼360 ps and a full width at half-maximum of ∼576 ps are obtained in the Ag/SrTiO3/Ag photodetectors under the illumination of a 355 nm laser with 15 ps duration. These results provide a useful guide for designing high-performance photodetectors based on perovskite oxides and the appropriate metal electrode selected.