Fabrication and characterization of metal–semiconductor–metal ultraviolet photodetector based on rutile TiO2 nanorod

Abstract

The fabrication and characterization of a metal–semiconductor–metal ultraviolet photodetector are studied. The photodetector is based on TiO2 nanorods (NRs) grown on p-type (111)-oriented silicon substrate seeded with a TiO2 layer is synthesized by radio frequency reactive magnetron sputtering. A chemical bath deposition is used to grow TiO2 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 TiO2 NRs. Optical properties are further examined using photoluminescence spectroscopy. A sharp and high-intensity UV peak at 367nm is observed in comparison with visible defect peaks centered at 432 and 718nm. Upon exposure to 365nm light (2.3mW/cm) at 5V bias, the device displays 76.06×102 sensitivity, internal photodetector gain of 77.06, photocurrent of the device is 2.62×10−5A and photoresponse peak of 69.7mA/W. The response and recovery times are calculated as 18.5 and 19.1ms upon illumination to a pulse UV light (365nm, 2.3mW/cm2) at 5V 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.