We report a ZnO-based thin film transistor UV photodetector with a back gate configuration. The thin-film transistor (TFT) aspect ratio W/L is 150 μm/5 μm and has a current on-off ratio of 10 10. The detector shows UV-visible rejection ratio of 10 4 and cut-off wavelength of 376 nm. The device has low dark current of 5 × 10 -14 A. The persistent photoconductivity is suppressed through oxygen plasma treatment of the channel surface which significantly reduces the density of oxygen vacancy confirmed by XPS measurements. The proper gate bias-control further reduces recovery time. The UV-TFT configuration is particularly suitable for making large-area imaging arrays.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)