Seminars

In situ scanning and transmission electron microscopy of nanostructured materials

March 29, 2019
Authors: Prof. Andrea Falqui,
Biological and Environmental Sciences and Engineering Division,
King Abdullah University of Science and Technology (KAUST),
Saudi Arabia

Since about fifteen years Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and
Scanning TEM (STEM) knew a new flourishing due to the commercial availability of ultra-bright field emission
electron sources, allowing to perform both much faster imaging and compositional analyses. Furthermore, TEM
and STEM development was further dramatically pushed by the invention of spherical aberration correctors for
the TEM objective lens and the STEM condenser one, permitting to get unprecedented point resolution, down to
less than 0.1 nm, using conventional electron acceleration voltages. As a consequence, all these achievements
strongly promoted a terrific progress of in situ Electron Microscopy, both SEM- and TEM-based, which consists
in live-imaging several dynamic processes occurring to the investigated sample as a consequence of an external
stimulus. With this aim, novel and dedicated specimen holders were designed, of which the main feature is the
concomitant capability to tune the external stimulus (heating, biasing, indenting, etc.) with very high precision
and speed, and to reduce down to few nanometers per minute the sample’s spatial drift.
I’ll first provide with a general overview of the above-mentioned impressive improvements of both (S)TEM
and SEM in situ imaging and analytical capabilities, paying particular attention to those related to the specimen
heating. I will describe the in situ thermally-driven evolution of nanosized gold polycrystals with different
starting density, imaged by a TEM approach. Second, I will show the thermally-driven time evolution of
nanoporous gold’s 3D structure, studied by a smart combination of in situ heating SEM and Serial Block Face-
SEM, i.e., ultramicrotomy performed inside a scanning electron microscope.

Referent: Paolo Milani

Poster: falqui2_2279