Highly sensitive ultraviolet sensor based on ZnO nanorod film deposited on ST-cut quartz surface acoustic wave devices

• Published in: Surface & coatings technology Vol. 363; pp. 419 - 425
• Main Authors: Li, W., Guo, Y.J., Tang, Q.B., Zu, X.T., Ma, J.Y., Wang, L., Tao, K., Torun, H., Fu, Y.Q.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 15.04.2019; Elsevier BV
• Subjects: Light; Luminous intensity; Nanorods; Quartz; Resonant frequencies; SAW device; Sensitivity enhancement; ST-cut quartz; Surface acoustic wave devices; Surface acoustic waves; Ultraviolet detectors; Ultraviolet radiation; UV detector; Zinc oxide; Zinc oxides; ZnO nanorods; ZnO nanorods; UV detector; SAW device; ST-cut quartz
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/j.surfcoat.2019.02.041

A highly sensitive surface acoustic wave (SAW) ultraviolet (UV) detector operated at room temperature was developed using a sensing layer of zinc oxide (ZnO) nanorods (NRs) grown on ST-cut quartz using a hydrothermal method. Under illumination of the UV light with a wavelength of 365 nm and an intensity of 6 μW cm−2, the resonant frequency of the SAW UV sensor based on ZnO NRs/ZnO nanofilm structure was decreased by ~200 Hz, mainly due to electroacoustic effect. The estimated enhancement in the sensitivity based on the experimental results is ~3.5 folds compared to a device with only a thin nanolayer ZnO film. Meanwhile, density of ZnO NRs over the ZnO seed layer was also investigated and an optimum design was proposed. •We have systematically explored ZnO nanorods (NRs) on ST-cut quartz SAW devices for UV sensing.•We varied the density of NRs over the seed layer to optimize the device for UV sensing.•We experimentally validated that a density of 35% is optimum.•Under a low UV light intensity of 6 μW cm−2, the frequency of the SAW UV sensor based on ZnO NRs decreases by ~200 Hz.