Microscopy and Microanalysis

STEM Development and Applications

D-STEM: A Parallel Electron Diffraction Technique Applied to Nanomaterials

K.J. Ganesha1, M. Kawasakia2, J.P. Zhoua1 and P.J. Ferreiraa1 c1

a1 Materials Science and Engineering, The University of Texas at Austin, 1 University Station, C2200, Austin, TX 78712, USA

a2 JEOL, USA Inc., 11 Dearborn Rd., Peabody, MA 01960, USA

Abstract

An electron diffraction technique called D-STEM has been developed in a transmission electron microscopy/scanning transmission electron microscopy (TEM/STEM) instrument to obtain spot electron diffraction patterns from nanostructures, as small as ∼3 nm. The electron ray path achieved by configuring the pre- and postspecimen illumination lenses enables the formation of a 1–2 nm near-parallel probe, which is used to obtain bright-field/dark-field STEM images. Under these conditions, the beam can be controlled and accurately positioned on the STEM image, at the nanostructure of interest, while sharp spot diffraction patterns can be simultaneously recorded on the charge-coupled device camera. When integrated with softwares such as GatanTM STEM diffraction imaging and Automated Crystallography for TEM or DigistarTM, NanoMEGAS, the D-STEM technique is very powerful for obtaining automated orientation and phase maps based on diffraction information acquired on a pixel by pixel basis. The versatility of the D-STEM technique is demonstrated by applying this technique to nanoparticles, nanowires, and nano interconnect structures.

(Received August 19 2009)

(Accepted March 20 2010)

Correspondence:

c1 Corresponding author. E-mail: ferreira@mail.utexas.edu