Chemistry Reference
In-Depth Information
Fig. 5.21
HR-TEM
magnification of a zone of the
core-shell wire where good
crystalline quality areas are
near to planar defects
Fig. 5.22
TEM-HAADF
image of a core-shell
nanowire. The particle on the
tip is brighter because of the
presence of higher atomic
number elements (Iron,
Z
=
26)
different atomic numbers (Z) and highlights those with higher Z. In this case it
shows the presence of iron in the particle on the tip, suggesting a mechanism of so
called “float growth” (Kolasinski
2006
) kind.
TEM-EDX analysis (Fig.
5.23
) carried out on the particle reveals the presence
of iron and silicon: this composition could suggest an iron-silicon alloy forming the
particle.
The presence of a silicon carbide core and silicon oxide shell is confirmed by
TEM- EDX elemental maps on the body of the nanowires (Figs.
5.24
and
5.25
).
