Performance enhancement of Love wave sensor via a cost-effective and robust dual-layered waveguide

Abstract

Love wave sensors have attracted significant attention due to their high sensitivity and compatibility with liquid environments for biosensing applications. However, conventional waveguide designs face challenges including thick film requirements (2%–11% wavelength), complex multilayer processing, and film delamination issues. Here, we demonstrate a dual-layered SiO2/Cr/Au/Cr waveguide structure that achieves enhanced performance with dramatically reduced thickness (<1% wavelength). The metallized boundary condition enables efficient surface wave mode confinement, while simultaneous deposition of the Cr/Au/Cr layer during IDT fabrication eliminates additional processing steps. The optimized 150 nm SiO2/100 nm Au sensor exhibits gravimetric sensitivity of 3.63 ppm/(ng/mm2), insertion loss of −19.14 dB, and linear response to 405 ng/mm2. This cost-effective approach provides a practical pathway for high-performance Love wave sensors in chemical and biological sensing applications.