The double heterostructure: the concept and its applications in physics, electronics, and technology (Nobel lecture).

The art and science of heterostructure design has not remained still since its founding: While the theoretical principles initially advanced rapidly, experimental realization initially lagged until the ideal AlGaAs solid solutions were found. From this point, development into application proceeded apace. In this Review, these intial steps and the current position of heterostructure applications are surveyed. New developments, such as the inclusion of quantum dots into heterostructures-with its concomitant world-record threshold current for laser activity-and future challenges are also elucidated.