Herbert Kroemer held his Nobel Lecture on 8 December 2000, at Aula Magna, Stockholm University. He was presented by Professor Stig Hagström.

Herbert Kroemer held his Nobel Lecture on 8 December 2000, at Aula Magna, Stockholm University. He was presented by Professor Stig Hagström.

Summary: Heterostructures, semiconductors with several thin layers of material separated by different band gaps, are used to make very rapid transistors and lasers of the type used in telecommunication technology. The general design principles of heterostructures were laid out in the 1950s, and these are explained in detail, pointing out problems in implementing heterostructures like valence and lattice matching. Various examples are described to illustrate the richness of phenomena that can be achieved with heterostructure devices.