UV Photodetection from a p–n Junction-Based GLAD-Fabricated Au/n-TiO2 NW/p-Si Device

Glancing-angle deposition technique was adopted to fabricate a vertical titanium dioxide (TiO 2 ) nanowire (NW) array over p-type Si substrate. The structural formation of the TiO 2 NW array was studied using transmission electron microscopy. Moreover, X-ray diffraction characteristics confirmed that the fabricated TiO 2 NWs were crystalline in nature. The recombination states of the synthesized TiO 2 NW array were also studied using photoluminescence characterization. The Au/TiO 2 /p-Si device showed a very low dark current of 0.163 µ A/cm 2 at +0.5-V applied voltage. Under exposure of light, a significant amount of electron–hole pairs were generated and separated by an external electric field. The device also exhibited a large responsivity, low noise-equivalent power and high detectivity of 19.8 A/W, 3.9 × 10 −14 W and 8.7 × 10 13 Jones, respectively, at 400 nm of illumination with low light power density of 1.07 µ W/cm 2 . Moreover, the fabricated device gave a fall time and rise time of 75 ms and 350 ms, respectively The fabricated Au/TiO 2 /p-Si device formed a good-quality p–n junction between TiO 2 (n-type) and p-Si, making it a promising candidate for photodetector application.