HIGH-Q MERIT FACTOR, LOW-FREQUENCY ACOUSTIC RESONANT MODES FROM A PT(100) SINGLE-CRYSTAL

A spectroscopic technique, acoustic wave resonance spectroscopy (AWRS) , has been developed to study the influence of long wavelength acousti c phonon excitations on surface chemical processes. Results are presen ted which demonstrate the sensitivity of AWRS to the state and composi tion of a Pt{100} single crystal sample, using an ultrahigh frequency and amplitude resolution acoustic spectrometer, a vector analyzer. A n ovel part of the ultrahigh vacuum compatible excitation system is a re tractable piezo holder allowing the lithium niobate piezo transducer t o be moved in situ into the bonding position against the side of the s ample. Very sharp acoustic resonant modes with a Q merit factor of 1 x 10(4) appear only when the sample is clean. Carbon contamination redu ces drastically both the intensity and the density of the peaks. (C) 1 996 American Institute of Physics.