Visualizing subsurface defects in graphite by acoustic atomic force microscopy

Tian Wang; Chengfu Ma; Wei Hu; Yuhang Chen; Jiaru Chu

doi:10.1002/jemt.22668

Visualizing subsurface defects in graphite by acoustic atomic force microscopy

Microsc Res Tech. 2017 Jan;80(1):66-74. doi: 10.1002/jemt.22668. Epub 2016 Apr 18.

Authors

Tian Wang¹, Chengfu Ma¹, Wei Hu², Yuhang Chen¹, Jiaru Chu¹

Affiliations

¹ Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei, 230026, China.
² Computational Research Division, Lawrence Berkeley National Laboratory, Berkeley, California, 94720, USA.

PMID: 27087240
DOI: 10.1002/jemt.22668

Abstract

We describe a versatile platform, which combines atomic force acoustic microscopy, ultrasonic atomic force microscopy and heterodyne force microscopy. The AFM system can enable in-situ switching among these operation modes flexibly and thus benefit the discrimination of differences in mechanical properties and buried subsurface nanostructures. We demonstrate the potential of this platform for visualizing the subsurface defects of graphite. Our results show that tiny topographic edges are enhanced in acoustic oscillation signals whilst embedded defects and inhomogeneous in mechanical properties are made clearly distinguishable. The possibility of detecting subsurface defects in few-layer graphene is further discussed with first-principles calculations. Microsc. Res. Tech. 80:66-74, 2017. © 2016 Wiley Periodicals, Inc.

Keywords: atomic force acoustic microscopy; graphite; heterodyne force microscopy; subsurface nanoimaging; ultrasonic atomic force microscopy.