Biomedical Engineering Reference
In-Depth Information
2.9 Electron microscopy images and chemical characterization of a-
Fe
2
O
3
fractals synthesized with a K3[Fe(CN)6] concentration of 0.015m
at 14088C. (a) Low-magnification SEM image of fractals showing the
high yield and good uniformity. (b) SEM image of a single a-Fe
2
O
3
fractal taken from one side. (c) SEM image of a single a-Fe
2
O
3
fractal
taken from the other side. (d) Higher magnification image of a single a-
Fe
2
O
3
fractal showing striking periodic corrugated structures on the
main trunk. (e) XRD pattern of the sample confirming formation of a
pure a-Fe
2
O
3
phase;
= intensity. (f) M
¨
ssbauer spectrum of the sample
recorded at room temperature;
I
A
= absorption.
Oblique-angle vapor deposition offers advantages in the fabrication of
nanostructures over large areas. Vapor atoms arrive on the substrate at
oblique angles relative to the surface normal of the substrate. The evaporant
nucleates on the substrate and the region behind the nucleus does not receive
any further vapor because of the shadowing by the nucleus. Therefore,
vapor will be deposited only onto the nucleus. This gives rise to the
formation of isolated columnar structures. This technique requires no
templates, relatively low temperatures and less harmful chemicals in
nanostructure fabrication.
The preparation of thin films of Fe-Ni amorphous alloys by a simple
thermal evaporation technique has also been investigated. The focus is on
