Silicon and LEDs meet their match

17 Jun 2002

UK scientists have developed a silicon-based light-emitting diode that operates at room temperature.

KP Homewood and colleagues from the University of Surrey used dislocation engineering to force light from silicon, a feat that has baffled scientists for years.

"There is an urgent requirement for an optical emitter that is compatible with standard, silicon-based ultra-large-scale integration (ULSI) technology," reported the scientists in Nature 410 192. "Our LED achieves this, which allows immediate implementation on a standard fabrication line."

Key to the breakthrough is boron. The scientists added boron to silicon to form the potential junction that is fundamental to all semiconductor diodes, and to introduce dislocation loops. According to the researchers the dislocation loops produce strains that confine the charge carriers, which have previously restricted silicon's radiative efficiency.

With non-optimized devices already achieving comparable efficiencies to conventional LED devices, Homewood and colleagues are excited. "The device forms the basis for the development of an injection laser," they claim. "Also the approach is not limited to silicon. Silicon carbide could produce devices that span the near-infrared region, which is important for optical fiber communications."