▎ 摘　　要

Low-cost and high-performance UV photodetector (PD) based on anatase titanium dioxide (TiO2) and nitrogen-doped graphene quantum dots (N-GQDs) bilayer heterojunction were fabricated on a commercial SiO2/Si substrate by drop-casting the N-GQDs solution on the surface of anatase TiO2 thin film, which was initially prepared by thermally oxidizing a DC-sputtered titanium (Ti) film in air. The anatase TiO2 and N-GQDs films were characterized with several techniques in order to study their structure and morphology properties. XRD, XPS, and AFM revealed that the phase of the as-sputtered Ti film transformed to a highly crystalline pure anatase TiO2 film when thermally oxidized at 600 degrees C in air. In addition, TEM, HRTEM, and FTIR revealed that the N-GQDs are highly crystalline and narrowly distributed in size. Furthermore, the optical and UV light harvesting properties of photodetectors based on pure anatase TiO2 film (without N-GQDs) and anatase TiO2 (with N-GQDs) were investigated. The photoresponsivity of the hybrid photodetector based on anatase TiO2/N-GQDs heterojunction has been enhanced by almost 2.5 times in magnitude than that of the photodetector based on pure anatase TiO2 film. This result was validated by elucidated energy band alignment between the anatase TiO2 and N-GQDs films, which resulted in a higher absorption rate, and an efficient transport mechanism in the hybrid junction-based photodetector than that of the pure TiO2-based photodetector.