Vapor sensing by means of a ZnO-on-Si surface acoustic wave resonator

Conference · Sun Jan 01 04:00:00 EST 1984

OSTI ID:6012509

Martin, S J; Schweizer, K S; Schwartz, S S; Gunshor, R L

Surface Acoustic Wave (SAW) devices can function as sensitive detectors of vapors. The high surface acoustic energy density of the device makes it extremely sensitive to the presence of molecules adsorbed from the gas phase. Mass loading by the adsorbate is the primary mechanism for the surface wave velocity perturbation. If the device is used as the frequency control element of an oscillator, perturbations in wave velocity on the order of 10 parts per billion may be resolved by means of a frequency counter. ZnO-on-Si SAW resonators have been examined as vapor sensors. The piezoelectric ZnO layer permits transduction between electrical and acoustic energies, as well as endowing the surface with particular adsorptive properties. These devices exhibit Q-values up to 12,000 at a resonant frequency of 109 MHZ. The resonant frequency of the device shifts upon exposure to a vapor-air mixture, with a transient response which is distinct for each of the organic vapors tested. Due to the permeability of the polycrystalline ZnO layer, the instantaneous reversibility of the resonant frequency shift is found to depend on the type of adsorbed molecule.

• Research Organization: Sandia National Labs., Albuquerque, NM (USA); Purdue Univ., Lafayette, IN (USA). School of Electrical Engineering
• DOE Contract Number: AC04-76DP00789
• OSTI ID: 6012509
• Report Number(s): SAND-84-1373C; CONF-8411119-3; ON: DE85003250
• Country of Publication: United States
• Language: English

Related Subjects

656000* -- Condensed Matter Physics
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CHALCOGENIDES
COATINGS
ELECTRICITY
ELEMENTS
FILMS
OXIDES
OXYGEN COMPOUNDS
PIEZOELECTRICITY
RESONANCE
SEISMIC SURFACE WAVES
SEISMIC WAVES
SEMIMETALS
SILICON
SOUND WAVES
SURFACES
ZINC COMPOUNDS
ZINC OXIDES