Porous Ag/TiO 2 ‐Schottky‐diode based plasmonic hot‐electron photodetector with high detectivity and fast response

Due to the advantages of narrow energy distribution of plasmonic hot‐electrons in Ag and the high density of states in the TiO 2 conduction band, an Ag/TiO 2 composite is considered to be an ideal combination to construct a plasmonic hot‐electron photodetector with high detectivity and a high response speed. In this work, we fabricate a porous Ag/TiO 2 ‐Schottky‐diode based plasmonic hot‐electron photodetector. This detector shows a high detectivity of 9.8 × 10 10 cmHz 1/2 /W and a fast response speed, with a rise and fall time of 112 μs and 24 μs, respectively, under 450 nm light illumination at zero bias voltage. In addition, the height of the Ag/TiO 2 Schottky barrier can be decreased by removing the chemisorbed oxygen from the surface of TiO 2 with ultraviolet light illumination, and as a result, the responsivity of the Ag/TiO 2 plasmonic hot‐electron photodetector at 450 nm can increase from 3.4 mA/W to 7.4 mA/W.