UV detector characteristics of ZnO thin film deposited on Corning glass substrates using low-cost fabrication method

A UV detector based on the zinc oxide (ZnO) thin film was fabricated by using sol–gel process with zinc acetate dehydrate (Zn(CH3COO)22H2O) as a precursor. The hexagonal crystal structure of the ZnO sample was revealed by X–ray diffraction patterns (XRD). Field emission scanning electron microscopy (FESEM) results indicated that the ZnO film’s surface is smooth and uniform, having grain size of about 50 nm. Photoluminescence spectroscopy (PL) revealed UV light and broadband emissions, which were attributed to near band–edge (NBE) and deep level–edge emissions (DLE), respectively. The metal–semiconductor–metal (MSM) device based on the fabricated ZnO film showed a sensitivity of 43% upon exposure light (0.66 μW/cm2) at 5 V and a response peak of 4.3 A/W upon exposure to UV light, respectively. The UV detector showed excellent stability with time and a strong photocurrent response under 380 nm light. These results show a low-cost method of fabricating a high-performance ZnO MSM UV photodetector with a quick response, fast recovery, and high responsivity.