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Title: Characterization of two-dimensional hexagonal boron nitride using scanning electron and scanning helium ion microscopy

Characterization of the structural and physical properties of two-dimensional (2D) materials, such as layer number and inelastic mean free path measurements, is very important to optimize their synthesis and application. In this study, we characterize the layer number and morphology of hexagonal boron nitride (h-BN) nanosheets on a metallic substrate using field emission scanning electron microscopy (FE-SEM) and scanning helium ion microscopy (HIM). Using scanning beams of various energies, we could analyze the dependence of the intensities of secondary electrons on the thickness of the h-BN nanosheets. Based on the interaction between the scanning particles (electrons and helium ions) and h-BN nanosheets, we deduced an exponential relationship between the intensities of secondary electrons and number of layers of h-BN. With the attenuation factor of the exponential formula, we calculate the inelastic mean free path of electrons and helium ions in the h-BN nanosheets. Our results show that HIM is more sensitive and consistent than FE-SEM for characterizing the number of layers and morphology of 2D materials.
Authors:
 [1] ; ;  [2] ;  [3] ;  [4]
  1. Global Research Center for Environment and Energy Based on Nanomaterials Science National Institute for Materials Science (NIMS) 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan)
  2. International Center for Young Scientists, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan)
  3. State Key Laboratory of Silicon Materials, Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027 (China)
  4. Advanced Key Technologies Division, Global Research Center for Environment and Energy Based on Nanomaterials Science, and International Center for Young Scientists, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan)
Publication Date:
OSTI Identifier:
22280579
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 104; Journal Issue: 3; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 77 NANOSCIENCE AND NANOTECHNOLOGY; BORON NITRIDES; FIELD EMISSION; HELIUM IONS; HEXAGONAL LATTICES; ION MICROSCOPY; LAYERS; MEAN FREE PATH; MORPHOLOGY; NANOSTRUCTURES; SCANNING ELECTRON MICROSCOPY; SHEETS; SUBSTRATES; SYNTHESIS; TWO-DIMENSIONAL CALCULATIONS