Oh Puh-lease!

Robyn Williams: How did you make a nano Star of David?

Uri Banin: [I]n nanotechnology, one of the revolutionary ideas is to use chemistry not only to make the nanoparticles but also to incorporate them into devices... And to do that we are constructing nanoparticles which are more clever, more smart. It's a nanoparticle that not only has just a semiconductor material, which is the material that emits the light or a material which would be the components of a transistor, [but] also has a metallic part to it... We combined a nanoparticle which is made of copper sulphide and it is a highly faceted... very beautiful nanoparticle that we've made, about 14 to 20 nanometres in diameter, and then we've attempted to grow a metal on top of this nice nanoparticle in order to achieve this dual particle which has properties of combining a metal and a semiconductor together. And what we saw was a very interesting result which looked under the electron microscope like a nano Star of David. When you look up at this particle, which has a semiconductor of copper sulphide decorated by ruthenium, it really looks like the Star of David... We were of course fascinated by the actual structure that was formed. What happened was that it was a new growth made of a metal on a semiconductor particle because what we saw is that we actually decorate the edges of this particle. Instead of growing a metal island, the metal grew on the edges of the particles forming what looked from above like a Star of David, but in fact was a metal cage, a frame like a birdcage, but 100 million times smaller, surrounding this 20 nanometre particle, which was an additional benefit, discovering this in Jerusalem so close to Temple Mount." (Nanoparticles for diagnostics & light, The Science Show, Radio National, 13/11/10)