The distributions of surface oscillation and surface charges were probed within an interdigital transducer (IDT). The IDT was driven at a frequency of 39.5 MHz. The measurements with sub-μm spatial resolution were performed with a scanning acoustic force microscope. It utilizes the nonlinear interaction of the sample with the tip of a scanning force microscope. In the case of surface oscillation detection, this nonlinearity leads to a shift of the mean position of the cantilever due to varying oscillation amplitudes. The surface charges are mapped through the additional cantilever deflection caused by the attraction of the plates of the capacitor formed by the cantilever and the sample. Spatial distributions of the amplitude of surface oscillations and of surface charges at the end of a 39.5 MHz splitfinger IDT are presented. The obtained experimental results may lead to a deeper understanding in modelling of IDTs in the future.
Materials by design for sustainable solutions in the energy, medical, transport, and engineering sectors
