Plasmon-Sensitized Optoelectronic Properties of Au Nanoparticle-Assisted Vertically Aligned TiO2 Nanowires by GLAD Technique

In this paper, the glancing angle deposition technique is used to fabricate Au nanoparticle-assisted vertically aligned TiO2 nanowires (Au-NP-TiO2-NW) on glass and Si substrates. The effect of annealing on the plasmonic resonance and optical properties of Au-NP-TiO2-NW are investigated by UV-visible absorption and photoluminescence spectroscopy. The field emission gun-scanning electron microscopy with energy dispersive spectroscopy analysis manifests the successful growth of Au-NP-TiO2-NW on Si substrate with the presence of Au, Titanium (Ti), Oxygen (O), and Silicon (Si) in the sample. The transmission electron microscope and X-ray diffraction analysis reveal the polycrystalline nature of the anatase TiO2-NW and Au-NPs with improved crystal quality after annealing. The rectifying behavior of Au-NP-TiO2-NW/Si-based photodetector device under forward bias in dark condition demonstrates the formation of p-n junction at the interface of Au-NP-TiO2-NW and p-Si. The photocurrent and dark current density recorded for the device at 4 V are similar to 1.69 x 10(-3) and similar to 1.14 x 10(-3) A/cm(2), respectively. However, it is interesting to observe that an average similar to 60 folds photocurrent as compared with dark current with an excellent response time under the on/off switching of white light upon the device at -3 V, which confirms potential application in optoelectronics.