Microscopy and Microanalysis

Materials Applications

Identifying Hexagonal Boron Nitride Monolayers by Transmission Electron Microscopy

Michael L. Odlyzkoa1 and K. Andre Mkhoyana1 c1

a1 Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, USA

Abstract

Multislice simulations in the transmission electron microscope (TEM) were used to examine changes in annular-dark-field scanning TEM (ADF-STEM) images, conventional bright-field TEM (BF-CTEM) images, and selected-area electron diffraction (SAED) patterns as atomically thin hexagonal boron nitride (h-BN) samples are tilted up to 500 mrad off of the [0001] zone axis. For monolayer h-BN the contrast of ADF-STEM images and SAED patterns does not change with tilt in this range, while the contrast of BF-CTEM images does change; h-BN multilayer contrast varies strongly with tilt for ADF-STEM imaging, BF-CTEM imaging, and SAED. These results indicate that tilt series analysis in ADF-STEM image mode or SAED mode should permit identification of h-BN monolayers from raw TEM data as well as from quantitative post-processing.

(Received August 12 2011)

(Accepted January 10 2012)

Correspondence:

c1 Corresponding author. E-mail: mkhoyan@umn.edu