AUSTRALIAN scientists used lasers to induce micro-explosions in silicon, creating exotic new materials.
The techniques and the new materials could lead to easy-to-manufacture superconductors, light sensors and high-efficiency solar cells.
The researchers led by Professor Andrei Rode from The Australian National University (ANU) created two entirely new phases in silicon, and saw indications of potentially four more crystal arrangements.
According to Prof Rode, theory predicts the materials could have very interesting electronic properties, such as an altered band gap, and possibly superconductivity if properly doped.
The researchers reliably blasted tiny cavities into solid silicon, by burying the silicon under a clear layer of silicon dioxide, then focusing lasers on them. This creates extremely high pressure around the explosion site and forms the new phases.
Because of the complex structures of these phases, the physicists from ANU and University College London took a year to understand the nature of the new materials.
Using a combination of electron diffraction patterns and structure predictions, the team discovered the new materials have crystal structures that repeat every 12, 16 or 32 atoms respectively. The explosions made the structures more complex, opening up the possibility of having unusual or unexpected properties.
These complex phases are often unstable, but due to the scale of the explosions, the structures are small and cool very quickly, solidifying before they can decay. The new crystal structures have survived for more than a year now.
Conventional methods for creating materials with high pressure use tiny diamond anvils to poke or squeeze materials. By upgrading to ultra-short laser micro-explosions, researchers create pressures many times higher than what diamond anvils can produce.
The team’s new method promises a much cheaper and industrially-friendly method for large scale manufacturing of these exotic materials.

http://www.electronicsnews.com.au/news/laser-induced-micro-explosions-in-silicon-create-n