Dr Richard Tilley of Victoria University of Wellington describes what silicon quantum dots are and outlines some applications.
DR RICHARD TILLEY
Quantum dots and nanoparticles are semiconductor materials, so typical semiconductors are things like silicon or germanium. And the fantastic thing about quantum dots is that they have different properties compared to the bulk materials because of their small size. So one of the materials we are looking at is silicon, and a big piece of silicon just looks like a piece of metal – it’s very shiny and silvery. But when we make our silicon particles, we make them of only about 1.5 nanometres, so they really are minute. They are made up of maybe only 50 to 100 atoms. And when we make our silicon particles this small, we can actually get them to emit light, which bulk silicon will not do, and then we can use this property for different applications. To be able to see the quantum dots, what we have to do is shine some light onto them, some high energy light, say UV light, and then they will give out the different colours that we want to see. People are researching applications for them as light emitting diodes, or for lighting or even television screens, but what we are interested in is looking at biological applications for them.
Professor Kenji Yamaoto