Biomedical Engineering Reference
In-Depth Information
FIGURE 16.7
Images of the alumina replicas of the butterfly wing scales. (a) An optical microscope image of the alumina-
coated butterfly wing scales, of which the color changed from original blue to pink. (b) A low-magnification SEM image of the
alumina replicas of the butterfly wing scales on silicon substrate after the butterfly template was completely removed. (c) The
energy-dispersive X-ray (EDX) spectrum of the alumina replica shown in (b). (d) A higher-magnification SEM image of an
alumina-replicated scale, where the replica exhibits exactly the same fine structures. (e) An SEM image of two broken rib tips
on an alumina replica. Reprinted from Ref.
74
. Copyright © 2006, with permission from the American Chemical Society.
By annealing at 500 °C in air, the template was
removed and the resulting alumina replica
showed antireflective properties. Those were in
agreement with the original structure, with a
slight shift of the reflectance peak from 330 nm
to 375 nm. From the point of view of ALD pro-
cessing, this strategy could be adapted for tech-
nological applications, but the small size of the
