Squeezing light out of silicon

17 Jun 2002

Researchers in Italy have demonstrated optical gain in silicon, a crucial step in the development of a silicon laser. Such a device could revolutionize optical communications and microelectronics.

Bulk silicon is very inefficient at emitting light, and, currently, light-emitting electronic devices are made from compound-semiconductor materials, such as gallium arsenide and indium phosphide.

To squeeze the light out of silicon, Lorenzo Pavesi and his colleagues at the universities of Trento and Catania first implanted millions of silicon nanocrystals into a silicon dioxide matrix. When illuminated with a green laser, this structure emitted in the red region.

The next few steps on the way to making a silicon laser will be to build the nanostructures within an optical cavity to produce coherent light, and to replace the optical excitation with electrical stimulation. For the latter, novel structures, such as nanowires, could hold the key.