Effect of High–Temperature Annealing on Au Thin Film/TiO2 Nanowires for Enhanced Photodetection

Glancing angle deposition (GLAD) technique has been carried out to deposit the titanium dioxide (TiO
₂
) nanowires (NW) on the silicon (Si) substrate. The TiO
₂
NW is coated with a gold (Au) thin film (TF) and annealed at a very high temperature. The morphological characteristics have been reported using field emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HRTEM) analysis. The structural characteristics have also been reported using the X-ray diffraction (XRD) analysis. In the visible region, an overall 2.57 fold optical absorption enhancement has been observed. The annealed Au TF/TiO
₂
NW based device shows boosted photosensitivity (56 fold), improved rectification ratio (2.5 fold), low ideality factor (1.46), high detectivity (3 × 10
⁹
Jones), and low noise equivalent power (NEP) (2.92 × 10
⁻⁹
watt). All the improved electrical performances ensure that the annealed Au TF/TiO
₂
NW based device can be commercially used as a reliable photodetector.