Fabrication and characterization of metal–semiconductor–metal ultraviolet photodetector based on rutile TiO 2 nanorod

Abstract The fabrication and characterization of a metal–semiconductor–metal ultraviolet photodetector are studied. The photodetector is based on TiO 2 nanorods (NRs) grown on p-type (1 1 1)-oriented silicon substrate seeded with a TiO 2 layer is synthesized by radio frequency reactive magnetron sputtering. A chemical bath deposition is used to grow TiO 2 NRs on Si substrate. The structural and optical properties of the obtained sample are analyzed by using X-ray diffraction and field emission-scanning electron microscopy. Results show a tetragonal rutile structure of the synthesized TiO 2 NRs. Optical properties are further examined using photoluminescence spectroscopy. A sharp and high-intensity UV peak at 367 nm is observed in comparison with visible defect peaks centered at 432 and 718 nm. Upon exposure to 365 nm light (2.3 mW/cm) at 5 V bias, the device displays 76.06 × 10 2 sensitivity, internal photodetector gain of 77.06, photocurrent of the device is 2.62 × 10 −5 A and photoresponse peak of 69.7 mA/W. The response and recovery times are calculated as 18.5 and 19.1 ms upon illumination to a pulse UV light (365 nm, 2.3 mW/cm 2 ) at 5 V applied bias. These results demonstrate that the fabricated high-quality photodiode is a promising candidate as a low-cost UV photodetector for commercially-integrated photoelectronic applications.