  Nanotechnology research requires the routine use of characterization methods
with high spatial resolution. These experiments are rather costly, not only
from the point of view of the expensive microscopes, but also considering the
need of a rather specialized equipment operator. Here, we describe the
construction of an inexpensive and simple device that allows the analysis of
nanoparticle in a FEG-SEM; images can be generated at high magnifications (ex.
x500.000) and with nanometric resolution. It is based on the acquisition of
transmitted electrons annular dark field (TE-ADF) signal; the systems can carry
up to 16 TEM samples and, it is compatible with SEM sample exchange air-lock.
Performance test have shown the measured ADF signal showed the atomic number
and thickness dependence for transition metal nanoparticle about 10 nm in
diameter. Also, the signal quality is high enough that the determination of the
histogram of size distribution can be performed using a conventional image
processing software, for gold particles in the range of 2-10 nm in diameter.
The developed ADF device allows a much faster and cheaper high spatial
resolution imaging of nanoparticle samples for routine morphological
characterization and, provides an invaluable high throughput tool for an
efficient sample screening.
