A bright future for silicon quantum dots.

• Position: Nanocrystals

The first ordered arrays of silicon nanocrystals reported to date have been fabricated by scientists at the University of Texas, Austin, and Cornell University, Ithaca, N.Y. Brian A. Korgel, professor of chemical engineering at UTA, and his colleagues developed a chemical method to generate tiny silicon crystals--or quantum dots--with precisely controlled size and then relied on nature to organize them into regular structures. The new self-assembled arrays, presented in the journal ChemPhysChem, could help researchers exploit the promising light-emitting properties of one of the most commercially important semiconductors.

Bulk silicon is used in a wide range of applications, mainly in the electronics industry, but it is a weak light absorber and an extremely poor light emitter, so it is not suitable for uses that require light emission. These properties change when the crystal shrinks to nanoscale. Si quantum dots can exhibit very bright visible luminescence with size-tunable color, which make them interesting for the fabrication of light-emitting diodes (LEDs)--or even as a possible laser source. During recent years there has been great interest in understanding these unique properties and using them to create new technologies.

However, most of the applications require arrays of nanocrystals and, although there have been efforts to fabricate them, the...