Device goes for the glow.

Silicon, already the staple material of computers and electronics, would become even more useful if it could be made to glow. But its crystalline wafers, though friendly to electrons, turn a cold shoulder to photons, emitting light only weakly.

Zheng H. Lu, a materials scientist at the National Research Council of Canada in Ottawa, and his colleagues, however, have found a way to coax the stubborn crystals into luminescence. In the Nov. 16 Nature, they describe a method of stacking alternating layers of silicon and silicon dioxide to create a structure that can convert electron energy into light.

The scientists layered extremely fine sheets of the two materials-like sheets of filo dough-to create a "silicon superlattice." The light emission, they explain, arises from "quantum confinement" of electrons in the material's layers.

Quantum confinement occurs when electrons become penned into nanometer-sized spaces. Thus confined, they behave more like trapped waves than particles. Transitions between trapped wave states can then lead to emission of photons.

Given the increasing importance of optoelectronics for computing, telecommunications, compact disks, and holography, such silicon-based light generators could prove "an attractive option," says David A.B. Miller, who is a materials scientist at AT&T Bell Laboratories in Holmdel, N.J.

These new results show "strong evidence" that quantum confinement occurring in such superlattices may "allow us to turn silicon into a shining example of an optoelectronic material," Miller says in Nature. "This work will surely stimulate more activity in this field and may yet give silicon an even brighter future."