VILLIGEN, Switzerland Researchers from three Swiss universities claim to have found a route to efficient silicon light-emitting lasers. The new technique holds out the promise of practical integrated optoelectronic systems that could be manufactured in established silicon germanium fab lines.
Using a quantum-cascade (QC) laser architecture realized in a silicon and SiGe system, the team has demonstrated laser light emission with the same quantum efficiency as light generated in compound-semiconductor QC lasers. The work was a collaboration among the Paul Sherrer Institut here, the University of Neuchatel and ETH, a technical institute in Zurich.
Attempts to integrate lasers and silicon-based circuits have stumbled on the problems of using gallium arsenide or indium phosphide LEDs with physically incompatible silicon circuits. SiGe devices can be used to create laser diodes, but an indirect bandgap effectively blocks efficient light emission. With their QC laser, the Swiss team built a demonstration laser that generates and amplifies light emission using quantum-well transitions within the same band.