Quasi-electric fields and band offsets: teaching electrons new tricks (Nobel lecture).

The invention and development of fast opto- and microelectronic components based on layered semiconductor structures, termed semiconductor heterostructures, is described herein. Such fast transistors are used in radio link satellites and the base stations of mobile telephones, for examples. Laser diodes built with the same technology drive the flow of information along fiber-optic cables, and may be found also in CD players, bar-code readers, and laser pointers. The double-heterostructure principle is also increasingly used in incoherent light-emitting diodes, for example in traffic lights and other light sources requiring colored visible light.