An ultraviolet sensor using spin–coated ZnO nanoparticles based on surface acoustic waves

This paper proposes an ultraviolet (UV) sensor based on surface acoustic waves (SAWs) using ZnO nanoparticles. The UV sensor consists of an UV-sensitive film and a piezoelectric substrate propagating shear–horizontal (SH) waves. The UV-sensitive film is fabricated using commercially available ZnO nanoparticles by a solution process. The material properties of the ZnO nanoparticle-based film were evaluated using scanning electron microscopy, photospectrometry, and X-ray diffraction. The characteristics of the SAW-based UV sensor were tested under UV light (λ = 365 nm) using a network analyzer and a commercial UV lamp. The sensitivity and the linearity of the SAW-based UV sensor are 180.43 Hz/μW and 0.932 in frequency shift and 0.14°/μW and 0.965 in phase shift, respectively. The fabrication of the newly developed SAW-based UV sensor is simple but shows comparable characteristics to sensors having a much more complex production process.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► We demonstrated a SAW based UV sensor with ZnO NP–based film. ► Polycrystalline ZnO film based on nanoparticles was deposited using aqueous solutions. ► The conductivity of ZnO NP–based film was increased under UV irradiation. ► Increasing the conductivity of ZnO NP–based film induced a reduction in SAW velocity. ► Increasing UV intensity increased a shift in the frequency and the phase.