Nobel Lecture by Zhores I. Alferov (46 minutes)Zhores I. Alferov held his Nobel Lecture December 8, 2000, at Aula Magna, Stockholm University. He was presented by Professor Stig Hagström. Summary: Electronic devices using heterostructures, semiconductors with several thin layers of material separated by different band gaps, were first produced in the 1960s. Fundamental physical phenomena in classical heterostructures are described. Alferov’s invention of the injection laser in the 1960s paved the way for communications with fibre optics. Future applications in, amongst other areas, solar energy are discussed.