AFM observation of surface acoustic waves emitted from single symmetric SAW transducers

Applied Physics Letters

Behme

2001

Self Cite

We present an experimental method for the high-resolution imaging of the excitation and propagation of surface acoustic waves (SAWs) on anisotropic piezoelectric substrates. By employing a scanning acoustic force microscope (SAFM), we are able to image acoustic waves that are excitable by a single circular electrode pair source through the mixing with well-defined reference plane waves. We show amplitude and phase images of the point-source wave field, containing the angular dependence of the phase velocity of these modes, as well as their electromechanical coupling strength. The SAFM allows easy access to acoustic material properties, which are important for the design of commercial SAW devices.

mentioning

confidence: 99%

High-resolution imaging of a single circular surface acoustic wave source: Effects of crystal anisotropy

Applied Physics Letters

Behme

2001

Self Cite

“…The study of wave excitation from an individual source is extremely challenging as the involved amplitudes are orders of magnitude below 1 nm. The experimental results [137][138][139][140] demonstrate the very high vertical resolution of the SAW-AFM which is smaller than 0.01 pm.…”

Section: Emission From Elementary Wave Sourcesmentioning

confidence: 86%

Surface acoustic wave-assisted scanning probe microscopy—a summary

2009

Rep. Prog. Phys.

Elastic properties of nanoscopic materials, structures and thin films are important parameters controlling their growth, as well as their optical and electronic properties. Acoustic microscopy is a well-established method for elastic imaging. In order to overcome its micrometer-scale diffraction-limited lateral resolution, scanning probe microscopy-based acoustic near-field techniques have been developed. Among the acoustic modes used for microscopy, surface acoustic waves (SAWs) are especially suited for probing very small and thin objects due to their localization in the vicinity of the surface. Moreover, the study of SAWs is crucial for the design of frequency filter devices as well as for fundamental physical studies, for instance, the probing of composite fermions in two-dimensional electron systems. This review discusses the capabilities and limitations of SAW-based scanning probe microscopy techniques. Particular emphasis is laid on the review of surface acoustic waves and their interaction with elastic inhomogeneities. Scattering, diffraction and wave localization phenomena will be discussed in detail. Finally, the possibilities for quantitative acoustic microscopy of objects on the nanoscale, as well as practical applications, are presented.

“…The experimental results demonstrate the very high vertical resolution of the SAFM which is smaller than 0.01 pm, in combination with nm lateral resolution. [41][42][43] The mapping of the wave field of single sources opens up new ways for the modeling and improvement of acoustic devices that is based on detailed measurements instead of empirical models. Figure 9 shows the first measurement of the excitation characteristics of a single acoustic source.…”

Section: Analysis Of Single Line-and Point-sourcesmentioning

confidence: 99%

Nanoacoustics: probing acoustic waves on the nanoscale

2003

SPIE Proceedings

Two scanning acoustic probe microscopy (SAPM) techniques have been developed for the nanoscale analysis of the interaction of acoustic modes on the surface of a solid. The scanning acoustic force microscope (SAFM) and the scanning acoustic tunneling microscope (SATM) are extensions to the scanning probe microscopy world utilizing the non-linearity of the respective interaction-distance curves in order to detect high-frequency signals, like acoustic waves or electric fields. SAFM and SATM measurements are presented that give an overview of past and present work in this field. With SAPM, acoustic wave properties of arbitrarily polarized surface acoustic wave (SAW) modes can be measured with sub-wavelength resolution and unmatched amplitude sensitivity. SAW dispersion measurements, scattering and diffraction, SAW transducer studies, studies of the crystal anisotropy, as well as atomically resolved images of the oscillating lattice will be discussed.