Single Semiconductor Quantum Dots

Worldwide, many researchers are fascinated from the rich physics of se- conductor quantum dots (QDs) and their high potential for applications in photonics and quantum information technology. QDs are nanometer-sized three-dimensional structures which con?ne electrons and holes in dimensions oftheircorrespondingDeBrogliewavelength.Asaresult, theenergylevelsare quantized and for that reason they are also often referred as arti?cial atoms. Epitaxially grown QDs which are the subject of this book are embedded in a solid state semiconductor matrix and their size, shape, composition, and lo- tion can be tailored to a large extent by modern growth techniques. In QDs, excitations can involve more than a single carrier and interaction among the carriers modify or even dominate the emission properties. Therefore, a simple two-level description is only appropriate under certain well de?ned expe- mental conditions. Tremendous progress has been obtained in understanding their electronic, optical and spin properties mainly by performing single dot spectroscopy and using appropriate theoretical models.