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Buckling nanoribbons take silicon in new direction

The technical program got off to a flying start as John Rogers captured the audience’s imagination with the idea of making stretchy silicon.

First, you’ve got to thin the silicon down to make it flexible. “There are basic etching tricks to do this,” he said, revealing SEM images to back up the claim. “What you end up with is a large quantity of nanoribbons.”

Next, you use a stamping process to move the thin strips of silicon into position on a substrate. “The wafer becomes an inking pad,” explained Rogers. “And you dry transfer print the nanoribbons on to your device substrate.”

Saving the best until last, he popped up a slide showing wavy silicon ribbons rising up and down across a rubbery PDMS film. The secret to creating the structure is to stamp the nanoribbons on to a pre-stretched substrate. When the surface is allowed to relax and shrink in size, the silicon buckles into a springy network that can be both stretched and compressed by as much as 50%. According to Rogers, in tests the substrate will often rupture before the silicon.

The team has already used the technique to make simple CMOS circuits, which leads me nicely on to my next post…

Posted by James Tyrrell on December 1, 2008 11:38 PM | Permalink