• Professor Jim Williams (L), Professor Andrei Rode and Associate Professor Jodie Bradby with the electron diffraction pattern of one of their new silicon phases. Photo credit: Stuart Hay, ANUProfessor Jim Williams (L), Professor Andrei Rode and Associate Professor Jodie Bradby with the electron diffraction pattern of one of their new silicon phases. Photo credit: Stuart Hay, ANU

ANU make new materials with micro-explosions

Scientists at the Australian National University (ANU) and the University College London (UCL) have created two completely new materials by firing lasers into silicon to create micro-explosions.

Professor Rode, a laser physicist at the ANU Research School of Physics and Engineering (RSPE) explained: "We've created two entirely new crystal arrangements, or phases, in silicon and seen indications of potentially four more. Theory predicts these materials could have very interesting electronic properties, such as an altered band gap, and possibly superconductivity…”

The scientists focused lasers onto silicon that is buried under a layer of silicon dioxide.  This way they can blast tiny cavities into the silicon, which creates extremely high pressure around the explosions site and forms the new phases.

Professor Jim Williams of the Electronic Material Engineering group at ANU, said: "The micro-explosions change silicon's simplicity to much more complex structures, which opens up possibility for unusual and unexpected properties."

There are already ways to create new materials by putting other materials under extremely high pressures, usually using tiny diamond anvils to poke or squeeze them. However, the laser micro-explosions create pressures many times higher and promises a cheaper and industry friendly method for large-scale manufacturing of the materials.

Dr Jodie Bradby, also from ANU Research School of Physics and Engineering, explained: "We reliably create thousands of micron-size modified zones in normal silicon within a second. The semiconductor industry is a multi-billion dollar operation - even a small change in the position of a few silicon atoms has the potential to have a major impact."

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