GHz surface acoustic wave ultraviolet sensor based on photo-conductive lamellar Molybdenum Disulfide

This article reports the fabrication and characterization of a highly sensitive ultraviolet (UV) sensor based on Zinc Oxide (ZnO)/glass surface acoustic wave resonator (SAWR) with lamellar Molybdenum Disulfide (MoS 2 ) as photo-conductive layer. The interdigital transducers (IDTs) with a periodicity of 2.4 μm were fabricated on SAWR by Electron Beam Lithography (EBL) technique, enabling a resonant frequency of 1.019 GHz in the SAWR. The SAWR UV sensor exhibited a linear up-shift in the frequency with UV intensity and a high sensitivity of 4.15 ppm/μW/cm 2 . The significant frequency-shift is attributed to high resonant frequency and excellent photoelectric properties of lamellar MoS 2 . The experimental results show the MoS 2 coated ZnO/glass-based SAWR have great promise for wireless ultraviolet sensor applications.