Microexplosions are being used to create new materials in research from Australia. Lasers are used to create ultrasmall explosions in silicon, the material most commonly used in computer processors.
Australian National University researchers found they could use the process to create exotic new materials. The silicon base was covered in a layer of silicon dioxide before being exposed to the laser beams, which created microexplosions which in turn produced the new materials. Investigators believe these could be used to develop a new generation of light sensors, solar cells, and other electronic devices.
"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 if properly doped," said Andrei Rode from ANU's Research School of Physics and Engineering (RSPE).
These strange structures took researchers roughly a year to analyze before the investigators released the results of their study. Investigators found the materials produced structures which repeated every 12, 16, or 32 atoms. Such structures are inherently unstable, but the small size of the molecules allows these formations to cool and solidify quickly before they degrade. The structures created in this study have remained intact for over a year.
"The microexplosions change silicon's simplicity to much more complex structures, which opens up possibility for unusual and unexpected properties," Jim Williams from RSPE told the press.
The team did a great deal of work before the experiment, learning how lasers would affect silicon, and what structures could be produced in such a scenario. Diamond presses exerting enormous pressures have been used before on silicon, in an effort to create new molecular structures. However, utilizing lasers to create microexplosions creates far more pressure than is possible using conventional methods. This process could, theoretically, produce these exotic materials on a commercial level for a far lower cost than using diamond anvils, the conventional process used to squeeze materials. Thousands of the tiny structures can be created in less than a second using the laser technique.
Silicon is able to act as a semiconductor, having properties of both a conductor and an insulator. This property makes the material ideal for use in electronic processors. However, making just small changes in the structure of the atoms in a chip can have great consequences for how electrons behave. This allows engineers to develop chips capable of a wide range of actions not possible with regular silicon.
Development of the new laser-based method for altering silicon was published in the journal Nature Communications.