Speaker
Description
Application of methods of X-ray diffraction on laboratory and synchrotron radiation sources, scanning electron microscopy (SEM) allowed to investigate the process of excitation and propagation of different types of surface acoustic waves in piezoelectric crystals (Rayleigh surface acoustic waves, pseudo-surface acoustic waves, Lamb waves).
While SEM method allows to visualize the acoustic waves in piezoelectric materials, X-ray diffraction methods allow not only to visualize acoustic wave fields in solids, but also to investigate by X-ray diffraction method and to obtain real information about the amplitudes of acoustic waves. Also X-ray diffraction methods allow us to determine the attenuation of acoustic waves along the depth of the crystal and along the direction of the surface acoustic wave propagation.
Different types of the surface acoustic waves (SAW) are excited by the same interdigital transducer (IDT), but at different frequencies. While Rayleigh surface acoustic waves are purely surface acoustic waves, pseudo-surface waves are waves that flow away deep into the crystal. Lamb waves are also excited by the same IDT, but from the opposite side of the crystal. The excitation and propagation of SAW in layered structures is also an interesting topic. The process of SAW propagation in the LiNbO3/Si bonded structure is considered. In this case IDT allows to excite the SAW in the single-crystal layer of LiNbO3, at the LiNbO3/Si interface and in the near-surface layer of Si. The SAW excitation frequencies are different because the SAW propagation velocities in different layers differ.
