Characteristics and Sensing of Sol-gel derived Titanium Dioxide-based Ultraviolet Photodetector on Flame Retardant-4 Board

Abstract

Titanium dioxide (TiO2) nanoparticles were successfully synthesised using a modified sol-gel method with titanium (IV) butoxide (Ti(OBu)4) as a precursor. The sol-gel derived TiO2 nanoparticles exhibited notable particle size reduction up to ∼ 60 % that of commercial TiO2 after heat treatment. In this work, ultraviolet (UV) photodetector of TiO2 was fabricated on a patterned Flame Retardant 4 (FR-4) board. The findings indicated that the photodetector exhibited remarkable stability and reproducibility. In particular, the UV photodetector exhibited high sensitivity (∼ 2764 %) and responsivity (∼ 66.14 mA/W) at 5 V bias under UV-A illumination. The responsivity of photodetector was also found to increase significantly when the bias was increased from 1 to 3 V, indicating that bias of 3 V was the optimum operating potential for the photodetector. Furthermore, the photodetector was capable of operating at low bias potential, with measured photocurrent density and dark current up to ∼ 47 μA/cm2 and ∼ 3 μA/cm2, respectively at 0.5 V. This work showed that TiO2-based UV photodetector fabricated from FR-4 is stable and highly sensitive and can be potentially applied in the UV photodetection domain.