Moving silicon atoms in graphene with atomic precision In recent yrs, it has become possible to see directly individual atoms using electron microscopy - esp. graphene, the 1-atom-thick sheet of carbon. Scientists have now shown how an #electron #beam can move silicon atoms through the #graphene #lattice without causing damage. The research combines advanced electron microscopy with demanding computer simulations. #METHOD: Due to the larger size of Silicon vs Carbon, these #dopant atoms protrude out from the plane. ~60 kiloelectronvolt electrons that Nion microscopes of both teams use for imaging the structure are not energetic enough to likely to ejection atoms BUT #C atoms next to a Si dopant are slightly less strongly bound, and can receive just enough of a kick to so that they #almost #escape from the #lattice, but are #recaptured due to an #attractive interaction with the silicon atom. ~Meanwhile, Si relaxes into to the lattice position left empty by the impacted C atom, which lands back into the lattice on #opp. side from where it started. ie silicon-carbon bond is #inverted >> directly seen by the microscopy teams. #USES: #atomic-scale #engineering: What makes our results truly intriguing is that the bond flip is #directional -- the silicon moves to take the place of the carbon atom that was hit by a probe electron, .....This means that it should be possible to #control the movement of one or more #silicon atoms in the lattice with atomic precision. So perhaps well see a new kind of #quantum #corral or an university logo made of silicon atoms in graphene in the near future, medienportal.univie.ac.at/presse/aktuelle-pressemeldungen/detailansicht/artikel/moving-silicon-atoms-in-graphene-with-atomic-precision/
Posted on: Sun, 14 Sep 2014 17:38:02 +0000
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