Preparation and application of sub-micron lead zirconium titanate surface acoustic wave biosensors

This paper presents the preparation of piezoelectric lead zirconium titanate (PZT) thick films and the fabrication of PZT surface acoustic waves (SAW) devices with sub-micron IDT electrodes by the micro-powder-sol-gel method. The utilization of these PZT SAW devices as biosensors to detect human IgG is also reported. From the experimental results, it was found that PZT thick films prepared from the precursor coating slurry solutions made from PZT micro-powders calcined at 550°C for 90 minutes have best electrical properties (¿_r=1889.355, Pr=29.3 ¿C/cm², Ec=32.4 kV/cm, d₃₁=-418.580 pC/N, d₃₃=916.681 pC/N at 1 kHz) after being annealed at 600°C for 1 hour. The central frequency and the insertion loss of PZT SAW devices prepared from PZT films mentioned above are 2.30 GHz and 16.14 dB, respectively. When used for the actual detection of human IgG, the detection of limit of PZT SAW biosensors is 10^-9 g/ml and is better than that of the QCM (10^-7 g/ml) under the same immobilization and sensing conditions.