A team of MIT researchers has discovered a new silicon compound that—get this—melts as it gets cooler, some 500 degrees Celsius lower than silicon's natural melting point. The researchers think it could eventually yield less expensive electronics.
While most materials transform from a solid to a liquid as they heat up, in some special cases they melt as they cool down—a phenomenon observed in a new compound comprised of silicon, copper, nickel and iron. Whereas silicon naturally melts at 1414 degrees C, the compound melts as it cools below 900 degrees C. With the compound, the silicon's impurities largely melt into liquid form, leaving a more pure silicon behind. PhysOrg explains:
The findings could be useful in lowering the cost of manufacturing some silicon-based devices, especially those in which tiny amounts of impurities can significantly reduce performance. In the material that Buonassisi and his researchers studied, impurities tend to migrate to the liquid portion, leaving regions of purer silicon behind. This could make it possible to produce some silicon-based devices, such as solar cells, using a less pure, and therefore less expensive, grade of silicon that would be purified during the manufacturing process.