Highly sensitive zinc oxide ultraviolet photodetector by titanium incorporation

In this study, zinc oxide (ZnO) thin films were prepared on glass substrates by the sol-gel chemical method with different Ti/Zn molar ratios. The electrical, optical, and structural properties of titanium doped ZnO thin films have been studied in detail. Interestingly, according to the electrical measurement results, there is a significant increase in resistivity and a decrease in carrier concentration of ZnO thin films with the addition of titanium. Ultraviolet-Visible (UV-Vis) spectrophotometer results show an increase in optical transmittance by 10 % in the visible region with the addition of titanium. Photoluminescence studies indicate that titanium addition causes a notable decrease in green and red emission peaks caused by structural defects of ZnO by showing a passivation effect. Moreover, the sensitivity to ultraviolet (UV) light was increased as high as 775 times in 3 % Ti-doped ZnO thin films. The specific detectivity of the samples increased by two orders of magnitude. Titanium doped ZnO films exhibit superior properties for UV sensors.