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New Insights on Subsurface Imaging of Carbon Nanotubes in Polymer Composites via Scanning Electron MicroscopyDespite many studies of subsurface imaging of carbon nanotube (CNT)-polymer composites via scanning electron microscopy (SEM), significant controversy exists concerning the imaging depth and contrast mechanisms. We studied CNT-polyimide composites and, by threedimensional reconstructions of captured stereo-pair images, determined that the maximum SEM imaging depth was typically hundreds of nanometers. The contrast mechanisms were investigated over a broad range of beam accelerating voltages from 0.3 to 30 kV, and ascribed to modulation by embedded CNTs of the effective secondary electron (SE) emission yield at the polymer surface. This modulation of the SE yield is due to non-uniform surface potential distribution resulting from current flows due to leakage and electron beam induced current. The importance of an external electric field on SEM subsurface imaging was also demonstrated. The insights gained from this study can be generally applied to SEM nondestructive subsurface imaging of conducting nanostructures embedded in dielectric matrices such as graphene-polymer composites, silicon-based single electron transistors, high resolution SEM overlay metrology or e-beam lithography, and have significant implications in nanotechnology.
Document ID
20170006922
Document Type
Reprint (Version printed in journal)
Authors
Zhao, Minhua (National Inst. of Standards and Technology Gaithersburg, MD, United States)
Ming, Bin (National Inst. of Standards and Technology Gaithersburg, MD, United States)
Kim, Jae-Woo (NASA Langley Research Center Hampton, VA, United States)
Gibbons, Luke J. (Virginia Polytechnic Inst. and State Univ. Blacksburg, VA, United States)
Gu, Xiaohong (National Inst. of Standards and Technology Gaithersburg, MD, United States)
Nguyen, Tinh (National Inst. of Standards and Technology Gaithersburg, MD, United States)
Park, Cheol (NASA Langley Research Center Hampton, VA, United States)
Lillehei, Peter T. (NASA Langley Research Center Hampton, VA, United States)
Villarrubia, J. S. (National Inst. of Standards and Technology Gaithersburg, MD, United States)
Vladar, Andras E. (National Inst. of Standards and Technology Gaithersburg, MD, United States)
Liddle, J. Alexander (National Inst. of Standards and Technology Gaithersburg, MD, United States)
Date Acquired
July 25, 2017
Publication Date
February 4, 2015
Publication Information
Publication: Nanotechnology
Volume: 26
Issue: 8
ISSN: 0957-4484
Subject Category
Composite Materials
Nonmetallic Materials
Report/Patent Number
NF1676L-20862
Funding Number(s)
WBS: WBS 432938.09.01.07.64
Distribution Limits
Public
Copyright
Other