A tip that never gets old

Posted on 19. Apr, 2012 by in Academic Departments, Engineering Physics, Issues, Magazine, Research

The nanotipWith colleagues at the University of Pennsylvania, and IBM Research-Zürich, UW-Madison engineers fabricated an extremely sharp nanoscale tip made from silicon carbide. The tip, which wears away at a rate of less than one atom per millimeter of sliding on a silicon dioxide substrate, is thousands of times more wear-resistant than previous designs. The advance may help make nanomanufacturing both practical and affordable.

Silicon carbide is an ideal candidate material for a tip. However, the team’s unique fabrication process made it possible to harden the surface, maintain the tip’s original shape, ensure strong adhesion between the hardened tip surface and the underlying material, says Engineering Physics Distinguished Research Professor Kumar Sridharan.

Using plasma-based ion implantation, he and colleagues exposed surfaces of nanoscale silicon tips to carbon ions and then heat-treated them for short durations at more than 2,000 degrees Fahrenheit to form a super-strong silicon-carbide layer. “When dealing with a plasma, it’s like trying to control lightning. We need to pull the ions from the plasma cloud and direct them to the ‘lightning rod,’ or tip, without blunting the tip,” says Sridharan. “If you strike the tip and blunt it, the whole thing is gone. We have to control the environment so that these tips can be made reliably en masse—and we’ve achieved that.”

Read a longer version of this story here.Bucky Badger head

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