Nanoscience advances on I06 - Growing nanowires
Scientists from the London Centre for Nanotechnology at University College London, Manchester University and Diamond have been using the Nanoscience Beamline (I06) to study the growth of tiny particles called nanowires, which could prove crucial in the development of nanoscale electronic components. This research has been published in the journal Nano Letters.
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| XPEEM secondary electron image of TiO2(110) after depositing Pd at 900 K. Image recorded with a 10 μm field of view. The photon energy is set at 420 eV so that Pd features are highlighted. |
Electronic devices are getting smaller all the time, and the challenge is to make the individual components as small as possible without affecting how they function. This includes the need for nanometre scale wires to be placed on electrically insulating substrates.
The group used a technique called metal vapour depositon to grow palladium nanostructures on a dielectric support. They then used Scanning Tunnelling Microscopy (STM, at UCL) to identify two distinct structures: roughly hexagonal islands and long thin wires just a few nanometres wide.
Although STM gave the group a good idea of the shapes of the nanostructures, it does not provide any information on their chemical make-up. Here they turned to the Nanoscience beamline at Diamond.
Using a technique called Low Energy Electron Microscopy they were able to identify the same nanoparticles after growing them at Diamond. Then they used X-ray Photoemission Electron Microscopy (XPEEM) to monitor the chemical state of individual nanoparticles on a particle by particle basis. By scanning the kinetic energy and creating a movie, the scientists determined that the nanoparticles were composed of metallic Pd, identifying a route for growing metallic nanowires on a dielectric substrate.
PhD student David Humphrey works in Geoff Thornton’s group at UCL.
David Humphrey, UCL
"Self assembled metallic nanowires on a dielectric support: Pd on rutile TiO2(110)", David S. Humphrey, Gregory Cabailh, Chi L. Pang, Chris A. Muryn, Stuart A. Cavill, Helder Marchetto, Alessandro Potenza, Sarnjeet S. Dhesi and Geoff Thornton
Nano Letters, 2009, 9(1), 155-159
DOI: 10.1021/nl802703e