Strong Quantum-Confined Stark Effect in Germanium Quantum-Well Structures on Silicon

light at the end of the chip Silicon chips dominate electronics while optical fibres dominate long-distance information transfer. Recent work, in search of the best of both worlds, has led to silicon devices capable of modulating light; these show promise but still rely on weak physical mechanisms found in silicon itself. Now a team working at Stanford University and at Hewlett-Packard's Palo Alto labs has developed thin germanium ‘quantum well’ nanostructures grown on silicon that generate a strong quantum-mechanical effect capable of turning light beams on and off. Their performance rivals the best seen in any material. This development may allow silicon/germanium chips to handle both electronics and optics, uniting computing and communications at the integrated chip level.