jMol
series
nanotwin ends
Here's a model of the {112} plane termination of
a {111} nanotwin in silicon, as viewed initially down
a <110> direction shared by twins to both left and
right. A {111} twin plane by itself is illustrated
here,
and a nanotwin (set of paired twin planes) internally
terminated on a {112} plane is illustrated
here.
This model focusses on atom positions just at the termination.
In the model below, atoms which have too many near neighbors
(more than 4) are colored red, while those with
too few near neighbors (less than 4) are cyan.
How might you expect the atoms to rearrange themselves
to lessen the discrepancy?
Below to the left find a comparison between an experimental
high-res electron microscope image (top: green)
of a "nanotwin end" in germanium, and a simulated image (bottom: grey)
of the jmol model above. Any ideas how to explain the
difference?
Here is a darkfield image of a pair of <111> nanotwins
found in gigascale integrated circuit silicon as manufacturers were
working to scale up to the routine production of 12 inch
diameter wafers.
Below find comparison between that experimental Ge
image and a physical model put together by Danielle K
for a Science Fair project.
