The ultraviolet responses of ZnO-based thin-film transistor prepared by sol–gel method

摘要

Bottom-gate and top-contact thin-film transistors with ZnO film as a channel layer were fabricatedby sol–gel method. The structural and optical properties of the deposited ZnO films wereinvestigated through X-ray diffractometer, scanning electron microscopy and UV–Visspectrophotometer. ZnO film has a high absorption in the ultraviolet region andc-axis orientationnormal to the substrate. The on/off current ratio, channel mobility and threshold voltage of ZnObased thin-film transistors in dark are 10~5,0.02 cm~2V~(−1) s~(−1) and 8.3 V, respectively. Under UVlight illumination (λ=365 nm) with an intensity of 2.4μW/cm~2, the drain–source current /_(DS) of thin-film transistor dramatically increases and the photo-to-dark current ratio is greater than 10~4.The transient response of the device to ultraviolet illumination is also discussed. The results mayopen the possibility of employing ZnO-thin-film transistors as UV photodetector.