Fabrication and characteristics of a surface acoustic wave UV sensor based on ZnO thin films grown on a polycrystalline 3C–SiC buffer layer

Zinc oxide (ZnO) thin films were deposited onto a polycrystalline (poly) 3C–SiC buffer layer for surface acoustic wave (SAW) ultraviolet (UV) sensing using a magnetron sputtering system. X-ray diffraction (XRD) and photoluminescence (PL) spectra showed that the ZnO film grown on 3C–SiC/Si had a dominant c-axis orientation, a lower residual stress, and higher intensity of luminescence at 380 nm of ZnO thin film. The SAW resonator UV detector were fabricated on ZnO/Si structures with a 3C–SiC buffer layer. The SAW resonator exposed under UV illumination had a linear response with sensitivity of 85 Hz/(μW/cm2) in ZnO/3C–SiC/Si structures, as compared to 25 Hz/(μW/cm2) in ZnO/Si structures with UV intensity varied until 600 μW/cm2.

► ZnO thin film by RF magnetron sputtering.
► 3C–SiC buffer layer reduced residual stress in ZnO film.
► SAW UV sensor with high sensitivity with 3C–SiC buffer layer.