Boosted photoresponsivity using silver nanoparticle decorated TiO <sub>2</sub> nanowire/reduced graphene oxide thin-film heterostructure
Prasenjit Deb, Jay Chandra Dhar
Abstract
Abstract Here, we report on the fabrication and use of a silver (Ag) nanoparticle (NP) decorated TiO 2 nanowire (NW)/reduced graphene oxide (RGO) thin-film (TF) heterostructure as a UV detector, using a controlled method called the glancing angle deposition technique. Transmission electron microscope images show Ag NPs (size 7–13 nm) covering the entire surface of the TiO 2 NWs. A high absorption as well as photoluminescence for the Ag NP-TiO 2 NW/RGO TF sample reveals the generation of a large number of electron–hole pairs compared to bare TiO 2 NW. The resulting plasmonic UV photodetector from the Ag NP-TiO 2 NW/RGO TF exhibits a rectification ratio of 5039 (+10 V) and responsivity of 1760 A W −1 at 350 nm light (with power density as low as 0.58 µ W cm −2 ). Moreover, the device shows fast response speed (rise time of 157 ms and fall time of 488 ms) with detectivity and noise equivalent power of 6.659 × 10 13 Jones and 51 fW, respectively. The enhanced plasmonic field and high scattering of light, along with the high mobility RGO layer at the bottom, result in the superior performance of the device.