  Nanogranular material systems are promising for a variety of applications in
research and development. Their physical properties are often determined by
grain sizes, shapes, mutual distances and by the chemistry of the embedding
matrix With focused electron beam induced deposition arbitrarily shaped
nanocomposite materials can be designed, where metallic, nanogranular
structures are embedded in a carbonaceous matrix. Using "post-growth" electron
beam curing, these materials can be tuned for improved electric transport or
mechanical behavior. Such an optimization necessitates a thorough understanding
and characterization of the internal changes in chemistry and morphology, which
is where conventional projection based imaging techniques fall short. Here, we
apply scanning transmission electron tomography to get a comprehensive picture
of the distribution and morphology degree of embedded Pt nanograins after
initial fabrication, and we demonstrate the impact of electron beam curing,
which leads to condensed regions of interconnected metal nanograins.
