Issue 6, 2017

Contrast mechanisms on nanoscale subsurface imaging in ultrasonic AFM: scattering of ultrasonic waves and contact stiffness of the tip–sample

Abstract

Ultrasonic atomic force microscopy (AFM) and its associated derivatives are nondestructive techniques that can elucidate subsurface nanoscale structures and properties. Despite the usefulness of these techniques, the physical contrast mechanisms responsible for the reported subsurface features observed in ultrasonic AFM are not well defined. In this study, we present a comprehensive model combining ultrasonic wave scattering and tip–sample contact stiffness to better reproduce the experimentally measured phase variations over subsurface features in two model systems. These model systems represent the two extreme sample types typically imaged by ultrasonic AFM, one being a hard material and the other a soft polymeric material. The theoretical analysis presented and associated comparisons with experimental results suggest that the image contrast depends on the combination of two contrast mechanisms: the perturbation of the scattered ultrasonic waves and the local variation of the contact stiffness at the tip–sample contact. The results of this study open up a new door for the depth estimation of buried nanoscale features into hard (engineering structures) and soft (polymers and biological structures) materials, and eventually lead to non-invasive, high-resolution 3D nano-tomography by ultrasonic AFM.

Graphical abstract: Contrast mechanisms on nanoscale subsurface imaging in ultrasonic AFM: scattering of ultrasonic waves and contact stiffness of the tip–sample

Supplementary files

Article information

Article type
Paper
Submitted
23 Nov 2016
Accepted
12 Jan 2017
First published
13 Jan 2017

Nanoscale, 2017,9, 2330-2339

Contrast mechanisms on nanoscale subsurface imaging in ultrasonic AFM: scattering of ultrasonic waves and contact stiffness of the tip–sample

H. J. Sharahi, G. Shekhawat, V. Dravid, S. Park, P. Egberts and S. Kim, Nanoscale, 2017, 9, 2330 DOI: 10.1039/C6NR09124E

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements