IMF2017

Surface Acoustic Waves (SAW) devices support the acoustic waves propagation on the surface and hence, any disturbance can be easily monitored making them suitable for sensing applications. On interaction of external stimuli with the acoustic wave, the velocity of the wave gets modified because of the mass loading, elastic loading or electric loading. Change in velocity results in the change in resonance frequency which can be transmitted and received easily with appropriate electronics, making them ideal for wireless applications. Rayleigh SAW devices show limited sensitivity in the presence of liquids due to damping. Some specific piezoelectric crystals with specific cuts can be used which support Shear horizontal SAW for liquid measurements. These waves (Love waves) can be further trapped on the surface of the device by coating a suitable layer of lower acoustic velocity over the device. In the present work, low cost Rayleigh SAW devices have been fabricated on corning glass substrates with sputtered Zinc oxide film. A suitable sensing layer is deposited over the IDT’s for gas sensing. The fabricated device is exploited detection of NO₂ gas efficiently. For the realization of biosensors, IDT’s have been patterned over 36°YX lithium tantalate. The fabricated devices were coated with ZnO thin film as a guiding layer. Microchannels of PDMS have been prepared using SU8 mould. The microchannels have been pasted over the love wave SAW device and have been used for detection of uric acid efficiently. The results clearly demonstrate the application of SAW devices for biosensing and gas sensing.