Waveguide ultrasonic force microscopy at 60 MHz

Inagaki, K. and Kolosov, Oleg and Briggs, G. Andrew D. and Wright, O. B. (2000) Waveguide ultrasonic force microscopy at 60 MHz. Applied Physics Letters, 76 (14). pp. 1836-1838. ISSN 0003-6951

Abstract

We present measurements using ultrasonic force microscopy at similar to 60 MHz, operating in a "waveguide" mode in which the cantilever base is vibrated and flexural ultrasonic vibrations are launched down the cantilever without exciting any particular cantilever resonance. The nonlinearity of the tip-sample force-distance curve allows the conversion of a modulated ultrasonic frequency into a low frequency vibration of the cantilever, detected in a conventional atomic force microscope. Images of Ge quantum dots on a Si substrate show contrast related to elasticity and adhesion differences, and this is interpreted with the Johnson-Kendall-Roberts model of the force-distance curve.