Solution-Processed UV and Visible Photodetectors Based on Y-Doped ZnO Nanowires with TiO₂ Nanosheets and Au Nanoparticles

Various chemical solutions were employed to fabricate the Au nanoparticles (NPs), TiO2 nanosheets, and Y-doped ZnO nanowires on glass substrates via the photochemical, sol–gel, and hydrothermal methods, respectively. The core–shell of the TiO2/ZnO:Y nanowires was dusted with Au nanoparticles. The ultrathin (2.48–7.02 nm) TiO2 nanosheet has a noncrystalline structure, and the various sizes (3.0–33.91 nm) of Au NPs enhanced the light absorption ability. The Au nanoparticles/TiO2 nanosheet/ZnO:Y nanowires featured a high UV on/off ratio of 1786.0 and various visible photoresponses of 154.1–27.3 with a variety of LEDs. Apparently, the coated noncrystalline TiO2 nanosheet improved the response speed. The external quantum efficiency of the sample was ∼5.1% and offered a higher responsivity in the visible light region due to the localized surface plasmon resonance effect.