Study of the Acoustoelectric Effect for SAW Sensors

    Authors

    B. H. Fisher;D. C. Malocha

    Comments

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    Abbreviated Journal Title

    IEEE Trans. Ultrason. Ferroelectr. Freq. Control

    Keywords

    SURFACE ACOUSTIC-WAVES; HYDROGEN DETECTION; ELECTRICAL-CONDUCTION; INTERACTION SPEED; BILAYER STRUCTURE; THIN-FILMS; PALLADIUM; SYSTEM; ABSORPTION; TRANSPORT; Acoustics; Engineering, Electrical & Electronic

    Abstract

    Research has recently begun on the use of ultrathin films and nanoclusters as mechanisms for sensing of gases, liquids, etc., because the basic material parameters may change because of film morphology. As films of various materials are applied to the surface of SAW devices for sensors, the conductivity of the films may have a strong acoustoelectric effect, whether desired or not. The purpose of this paper is to reexamine the theory and predictions of the acoustoelectric effect for SAW interactions with thin conducting or semi-conducting films. The paper will summarize the theory and predict the effects of thin film conductivity on SAW velocity and propagation loss versus frequency and substrate material. The theory predicts regions of conductivity which result in extremely high propagation loss, and which also correspond to the mid-point between the open and short-circuit velocities. As an example of the verification and possible usefulness of the acoustoelectric effect, recent experimental results of palladium (Pd) thin films on a YZ LiNbO(3) SAW delay line have shown large changes in propagation loss, depending on the Pd film thickness, exposure to hydrogen gas, or both. By proper design, a sensitive hydrogen leak detector SAW sensor can be designed.

    Journal Title

    Ieee Transactions on Ultrasonics Ferroelectrics and Frequency Control

    Volume

    57

    Issue/Number

    3

    Publication Date

    1-1-2010

    Document Type

    Article; Proceedings Paper

    Language

    English

    First Page

    698

    Last Page

    706

    WOS Identifier

    WOS:000275322400028

    ISSN

    0885-3010

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