Acoustic transducer based on ZnO nanorods

• Published in: 2017 IEEE 12th International Conference on Nano/Micro Engineered and Molecular Systems (NEMS) pp. 481 - 484
• Main Authors: Gaddam, Venkateswarlu, Neella, Nagarjuna, Rajanna, K., Veera Pandi, N., Nayak, M. M.
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01.04.2017
• Subjects: acoustic transducer; Acoustic transducers; Acoustics; hydrothermal synthesis; II-VI semiconductor materials; nanorods; piezoelectricity; Sensors; Steel; Substrates; Zinc oxide; ZnO
• ISSN: 2474-3755
• DOI: 10.1109/NEMS.2017.8017068

we report on ZnO nanorods based acoustic transducer for sound pressure level sensing applications. The sensing element is a circular diaphragm (diameter: 27 mm) of Stainless steel (SS-304L) substrate, which also acts as a bottom electrode for the developed transducer. Prior to synthesis of nanorods, ZnO seed layer (~100 nm) film was deposited by DC magnetron sputtering technique. ZnO nanorods were synthesized by hydrothermal method at lower temperature of 90 °C for 4 hrs growth duration. The average length and diameter of as- synthesized ZnO nanorods were 2 μm and 140 nm respectively. As-synthesized nanorods were used for the fabrication of acoustic transducer. The ZnO nanorods have been sandwiched between seed layer deposited on SS substrate and top electrode of silver epoxy (thickness: ~200 nm). The developed transducer is used for acoustic pressure sensing at different frequencies (31.5-2000 Hz) with different sound pressure levels (SPL) in the range of 120-160 dB. The acoustic sensing study was performed using the acoustic calibrator (Model NO: MAC 1001H) set-up. It was found that, the maximum peak to peak response of the transducer was 226 mV at 1 KHz excitation frequency with the SPL of 160dB. This is the first exploratory study on the applicability of ZnO nanorods based acoustic transducer. The possible potential applications are in consumer products (telephone circuits, speech amplifiers, tape recorder and hearing aids/microphones etc.), space, medical, strategic, automotive and industrial applications.